JPH039195B2 - - Google Patents

Description

The scope of the claims 1 To electrolytically reduce alumina to aluminum
a tank capable of wetting aluminum;
a cathode comprising a cathode substrate bonding a surface layer of
The surface layer is formed in a non-graphitized carbon matrix.
contains a refractory hard material, and the consumption rate of the carbon matrix is reduced.
The degree of abrasion of the refractory hard material during operation of the vessel is
essentially equal to the total rate of wear and dissolution, and
The surface layer is used to harden and carbonize the coated material.
obtained by twisting, The coating material is 10 to 90% by weight of a refractory hard material;
1 to 40% by weight non-graphitized thermosetting resin binder,
1 to 60 weight with particle size smaller than 100 mesh
% carbonaceous filler particles, and more than 100 mesh
Particulate matter and/or carbon with large particle size
Contains 5-70% carbonaceous additives by weight in fiber form
tank. 2. In the tank according to claim 1, the
Characterized by the refractory hard material containing titanium diboride
tank. 3. In the tank according to claim 2, the
The surface layer is 20-70% by weight of titanium diboride, 1-40% by weight.
Amount% thermosetting resin binder, 10-40% by weight carbon
filler, and 5-15% by weight of carbonaceous additives.
By curing and carbonizing the coating material containing
The tank that can be obtained. 4 Any of claims 1 to 3
In the vessel described, the thermosetting resin binder is
Enol resin, furan resin precursor or mixture thereof
A tank containing substances. 5 Any of claims 1 to 4
In the tank described, the surface layer is heated to 800-1000°C.
A tank exhibiting an expansion rate of less than 0.2%. 6. In the tank according to claim 1, the
The cathode is a tank tilted with respect to the horizon. 7 Wet aluminum for aluminum reduction tank.
A method for producing a cathode surface that moistens the surface of the cathode, the method comprising:
10-90% by weight refractory hard material in the body, non-graphitizing heat
1 to 40% by weight thermosetting resin containing curable resin
Mixture, 1 to 1 with particle size smaller than 100 mesh
60% by weight carbonaceous filler particles, and 100% by weight
Particulate matter and/or
is 5-70% by weight carbonaceous additive in the form of carbon fiber
applying a coating composition containing the coating composition;
Cures to form a relatively hard adhesive surface layer and
The surface layer is carbonized to form a durable material in the non-graphitized carbon matrix.
Presence of flammable hard substances, adhesive, aluminum
forming a wettable surface layer;
When the expansion rate (%) is 800 to 1000℃,
Expansion rate (%) of cathode substrate and 0.2 or less (including 0.2)
z) A method characterized by different things. 8 In the method set forth in claim 7,
The coating composition is applied to a carbon cathode block outside the bath.
It is applied to the tank, cured, and then placed in the tank.
A method characterized by: 9. In the method set forth in claim 8,
The coating composition is carbonized and then placed in the tank.
A method characterized by: 10. The method according to claim 8,
The coating composition is carbonized in the bath.
How to characterize it. 11. In the method according to claim 7,
The coating composition is applied to a carbon cathode blot outside the bath.
It is then hardened and carbonized in the tank.
A method characterized by: 12. In the method according to claim 7,
The coating composition is applied to a cathode substrate in the bath.
characterized by being hardened and carbonized.
Method. 13 Any of claims 7 to 12
The method according to claim 1, wherein the coating composition
A method characterized in that the coating is applied on a composite layer. 14 Any of claims 7 to 13
The method according to claim 1, wherein the coating composition comprises multiple
A method characterized in that it is applied in several layers. 15 Any of claims 7 to 14
In the method according to claim 1, the refractory hard material is
A method involving titanium diboride. 16 In the method described in claim 15
Therefore, the titanium diboride content changes sequentially in each layer.
A method characterized by: 17 Any of claims 7 to 16
In the method according to claim 1, the thermosetting resin bond
The agent may include one or more phenolic resins, furan resins,
A method containing a resin precursor or a mixture thereof. 18 Aluminum wettability for aluminum reduction tank
a cathode, comprising a cathode substrate having a surface layer
and the surface layer is a hardened and carbonized composition.
The composition contains 10 to 90% by weight of a refractory hard material;
1-40% by weight thermosets, including non-graphitized thermosets
chemical resin binder, particle size smaller than 100 mesh
1 to 60% by weight of carbonaceous filler particles having
Particulate matter with a particle size greater than 100 mesh
5-70% by weight of charcoal in the form of carbon fibers and/or carbon fibers
Cathode containing quality additives. 19 The cathode according to claim 18
and the thermosetting resin binder comprises one or more
phenolic resin, furan resin precursor or its
A cathode containing the mixture. 20 Claims 18 or 19
At the cathode, the composition has a refractory content of 20-70% by weight.
hard material, 1-40% by weight thermosetting resin, 10-40% by weight
40% by weight carbonaceous filler, and 5-15% by weight
Cathode containing carbonaceous additive. 21 As stated in Claims 18 to 20
In the cathode, the refractory hard material is silicon diboride.
The cathode is tan. 22 The cathode according to claim 18
and the cathode is inclined with respect to the horizontal line.
very. Background technology The production of aluminum has traditionally been carried out by Hall Heloux.
This is done using the electrolytic reduction method. using this method
dissolves aluminum oxide into molten cryolite,
Electrolyze at 900-1000℃. This method is suitable for
Ordinary steel wall with insulating lining for flammable materials
The process is carried out in a reduction tank containing The insulating lining
Additionally, it has a carbon lining in contact with the molten components.
Ru. One or more anodes, usually made of carbon, are connected to a DC power source.
It is connected to the positive electrode of the electrolytic cell and suspended into the electrolytic cell. same
One or more conductive rods connected to the negative pole of the DC power supply are
embedded in the carbon cathode substrate, including the floor of the tank.
Therefore, the cathode substrate becomes a cathode when a current is passed through it.
Ru. Smokeless if the cathode substrate contains a carbon lining
More common than charcoal, coke, and coal tar pitch
A large number of pre-baked cathode blocks compacted together with the mixture.
It is common for the cathode substrate to be made from rock.
Ru. In such a conventionally designed Hall-Helou electrolyzer,
This is the molten aluminum pool that forms during electrolysis.
itself acts as part of the cathode system. Cathode lining or
The average lifespan of cathode materials is 3 to 8 years, but under adverse conditions
It can be shorter at the bottom. cathode lining material
Deterioration is due to electrolyte and liquid aluminum erosion and
due to intrusion as well as intrusion of metallic sodium. this
Deterioration of carbon blocks and compacting mixtures
(rammingmix) causing expansion and deformation. One of the problems in operating an electrolyzer is that
Conventional changes in the surface of the carbon cathode under the minium reservoir
It was more present. For example, insoluble materials (sludge or
Estimation of mud (sludge) - forming an insulating part at the bottom of the electrolytic tank
It is -. Aluminum enters the iron cathode rod.
If the iron content in the aluminum metal becomes excessive,
tap-out in more severe cases.
out) occurs. Another serious drawback of carbon cathodes
is in that it is not wetted by the aluminum
be. For this reason, molten aluminum is applied to the cathode surface.
Significantly into the metal puddle for the purpose of effective contact.
It is necessary to have a height of Aluminum like this
One problem with maintaining a reservoir of
movement and movement in molten aluminum due to electromagnetic force.
A standing wave is generated. Short circuit between aluminum and anode
To prevent this, the anode-cathode distance (ACD) should be
Must be a safe 4-6 cm for most designs
Must be. When installing any electrolytic cell
Also, the lowest ACD value exists. If it is less than that,
A large loss in current efficiency occurs, but this loss is
Back reaction under new stirring conditions
Aluminum associated with increased back reaction
Aluminum is derived from the instability of mud.
This is due to a short circuit to the anode. current is electric
The electrical resistance of the distance between the electrodes across the solution is
Reduce voltage in the range of 1.4-1.7 volts. this
is 30-60% of the voltage drop in the electrolytic cell, and
This is the biggest cause of voltage drop in the tank. Reduces ACD and associated voltage drops
TiB as a cathode material for the purpose of₂fire resistant like
Research using hard materials (RHM) began in the 1950s.
It is widely practiced. TiB₂is very little
Aluminum melts into aluminum and becomes conductive.
moistened by minium. Because of this wettability
In this case, the aluminum film is directly on the RHM cathode surface.
Electrolytically deposited, eliminating the need for aluminum puddles
Become. TiB₂and similar RHMs are dampened by aluminum.
hydrated, resists the corrosive environment of the reduction tank, and has excellent
Since it is an electrical conductor, one reason is to make the ACD smaller.
Electricity using RHM for the purpose of saving energy
Many tank opening designs have been proposed. Conductive for electrolytic cells for aluminum production or refining
TiB₂Use of the elements is covered by the following U.S. patents:
Described; U.S. Pat. No. 2,915,442, no.
No. 3028324, No. 3215615, No. 3314876, No. 3330756
No. 3156639, No. 3274093, No. 3400061.
Rather widespread in the past as seen in these and other patents.
Extensive research efforts further explore TiB as a conductive element₂
Despite the potential benefits of using
Such compositions have gained industrial scale in the aluminum industry.
It seems that it has never been used as a model. Conventional technology
is TiB₂or does not accept RHM conductive elements
These substances are stable during use in an electrolytic reduction tank.
It is associated with lack of sexuality. According to reports,
These conductive elements break down relatively quickly during use.
Ru. This destruction occurs when the self-bonded RHM structure is exposed to electrolyte.
related to exposure to aluminum and/or aluminum intrusion.
As a result, the RHM structure is decisively weak.
As a result, cracks and destruction occurred. solid
Unfavorable effects when liquid phase invades interparticle boundaries
It is well known that this may occur. example
For example, oxygen impurities tend to separate along interparticle boundaries.
RHM tiles are made of aluminum metal and/or
The cryolite bath makes it susceptible to rapid attacks. Aluminum
TiB occurring in Ni electrolyzer₂Prevents tiles from collapsing
The conventional technology for
Industrially pure TiB₂3 times the cost of powder
contains less than 50ppm oxygen and is four times more expensive
Highly purified TiB₂Powder used in tile manufacturing
It was hot. Increased cost of tiles that require processing
Raise it to the top. However, as far as is known
is TiB₂An electrolytic cell using tiles is
No loss of tile adhesion or tile collapse
However, there is no example of successful long-term operation. RHM
Other possible reasons for failure of the oil and coating material
is molten aluminum or molten flux
(flux) or mechanical strength
and lack of resistance to thermal shock. Change
Another type of TiB₂Coating material applied to carbon substrate
However, TiB₂between the material and the carbon cathode block.
It was damaged due to the difference in thermal expansion. As far as we know,
Due to thermal expansion imbalance, bond strength problems, etc.
RHM-containing material successfully used as a commercial cathode substrate
has never existed until now. For example, approved by Kaiser Aluminum
U.S. Patent No. 1 by Lewis et al.
No. 3400061 is drained and wetted
Electrolysis with drained and wetted cathode
Teach tank structure. In this case, the RHM cathode surface
contains more than 5% carbon and usually 10-20% by weight pitch
RHM mixture baked at 900℃ or higher with binder
It's getting more familiar. According to this patent, such
Composite cathodes have higher dimensional stability than conventional cathodes
Ru. This composite cathode coating material is suitable for use at the bottom of the electrolytic cell.
Can be packed into position. However, this technology
was later approved by Kaiser Aluminum.
U.S. Patent No. 4,093,524 to Payne
susceptible to attack by electrolytic baths, as taught in
Therefore, it has not been widely adopted. The aforementioned U.S. Pat. No. 4,093,524 to Payne
TiB₂and other RHMs on conductive substrates (such as graphite) or
requests an improved method for bonding to silicon carbide.
Ru. The cathode surface is TiB with a thickness of 0.3 to 2.5 cm.₂With tiles
coming. However, such RHM tiles and carbon
Due to the large difference in thermal expansion coefficient between
A bond that is effective at any operating temperature of the cracking tank is
Difficult to form. Therefore, this bond is
Carbon reacts with carbon and carbonizes near the operating temperature of the electrolyzer.
Using the aluminum produced, RHM
Forms during operation at the interface between oil and carbon. but,
Bonds do not form until high temperatures are obtained, so the temperature step
Tiles move easily during tart operations. cathode surface
Bonding is accelerated by passing current through the surfaces, and
A thin aluminum carbide bond is formed. deer
However, if the distance between tiles is too large,
Aluminum and/or electrolyte attack occurs. Ma
If they are too close together, they will swell at operating temperatures.
corrosion occurs, resulting in rapid deterioration of the electrolyzer lining.
In addition, the operation of the electrolytic cell will be disrupted. Therefore, the above
This idea is not widely used. Holliday is US Patent No. 3,661,736
In Drained and Wetted
Request for inexpensive and dimensionally stable composite cathodes for electrolytic cells.
seek This composite cathode is embedded in a conductive matrix.
Particles or lumps of the RHM mixture melted by the soldering arc are
Contains. Base material is carbon or graphite and aluminum carbide
powders such as titanium, titanium carbide or titanium nitride
It is more similar to a chemical filler. However, such electrolysis
When the tank is operated, electrolyte and/or aluminum
However, the grain boundary alignment of the arc-melted RHM mixture is
most of the carbon or graphite matrix at a rate of about 1 cm per year.
Attack. This leads to premature destruction of the cathode surface.
Ru. U.S. Pat. No. 4,308,114 to Das et al.
Disclose cathode surface using RHM in graphite matrix
Ru. In this case, RHM is made with pitch binder
It is graphitized at temperatures above 2350℃. This cathode
Easy to destroy early due to rapid ablation
The graphite matrix may be subject to internalization and erosion.
be. In addition to the above patents, numerous other technologies
TiB₂Regarding the use of High purity, high density
Various types of TiB₂Tiles were tested, but they were
Generally has poor thermal shock resistance and is used in conventional electrolyzers.
Difficult to bond to carbon substrates. related to the mechanism of peeling.
The following factors are considered to be: (1) TiB₂heat between and carbon
High tension caused by the difference in expansion, and (2) tile surface
Due to the surface being wetted by aluminum,
between the tile and the adhesive that holds it in place
There is intrusion of aluminum into the interface. Add to peeling
In addition, due to the intrusion of aluminum into the interparticle boundaries,
tile disintegration, even with high purity tiles.
It can happen. These issues can be solved by TiB₂tile height
Along with cost, TiB in conventional electrolyzer₂of
Newly designed electrolyzer opens up widespread industrial use
TiB in₂The use of has been limited. of the present invention
The purpose is for surface coating of carbon cathode blocks and
Past attempts to use RHM for integral cathode surfaces
The attempt lies in overcoming the shortcomings. Summary of the invention The present invention relates to an improved electrolytic cell. In this electrolytic cell
is a refractory hard material (RHM), thermoset binder
systems, carbonaceous fillers and carbonaceous additives, and
A carbon-RHM coating composition containing a modifier in
This composition is applied to the carbon cathode and its
Cured in-situ and contains RHM in a carbonized bond matrix
The cathode surface becomes hard and strong. Electrolysis of the present invention
Carbonaceous additives used in the composition used for the cathode of the tank
As additives, carbon fibers - anti-cracking agents and tougheners are added.
Examples include -, which acts as a curing agent. Mitsuru
By adding a sufficient amount of RHM to the coating composition,
The extreme surface is constantly wetted by aluminum.
Therefore, this coating composition provides the benefits of RHM.
Economically and effectively given to the cathode, the more expensive
Eliminates the need for RHM tiles. BEST MODE FOR CARRYING OUT THE INVENTION Refractory hard materials (RHM), specific thermosets
applied to the cathode structure in combination with binders and other substances.
When the conventional carbon lining of the aluminum reduction tank
It has been found that the present invention provides an improvement. this
Structural integrity and low cost due to the use of coated cathodes
Benefits of traditional carbon linings such as RHM use
This results in the addition of desired properties that can be obtained more easily. mosquito
As an additional property, the coating with molten aluminum
Wettability, molten aluminum-to cryolite environment
Low solubility, good conductivity, and reduced mud build-up
There are few. Furthermore, the present invention can be applied to existing reduction tanks.
In that case, the cost and time of a complete tank redesign
is not necessary and the RHM type proposed by the prior art
high cost for manufacturing tile or RHM mixture tiles.
There is no need to strike. The coating composition of the present invention also includes:
It can also be used in tank designs using tilted cathodes. Certain clarifications and definitions may be helpful when also understanding the idea of the invention.
There is a need for justification. Therefore, the present invention
The following definitions shall be used. The "coating composition" used in the present invention includes RHM, carbon
from elemental additives, carbonaceous fillers, and binder systems.
Ru. In the present invention, "coating composition" or "coating material"
shall contain all of these substances. one
On the other hand, "coating" refers to drying, hardening, or carbonization.
Depending on the condition of the product, it may not contain all of the above substances.
Ru. This is because, for example, mix
liquid) evaporates and/or becomes heavy during curing and carbonization.
This is because there is a possibility that they will match. "Refractory hard materials" are generally classified as
Borides, carbides, silicides, and nitrides of group transition metals
(these are often called refractory hard materials)
), as well as mixtures thereof. "Resin binder" is a polymerizable and/or crosslinkable
Refers to thermosetting carbon materials. Coated as a reference to make the invention clear
The composition will also be explained. “Mix liquid” used in the present invention
varies in coating compositions depending on the content of the composition.
functions. Easily and evenly distributes solid components of coating compositions
Compositions that allow uniform mixing and are easily spreadable
can be given. Some like furfural
Mixtures of various types can be added to the coating composition.
It is also possible to increase the amount of carbonaceous filler.
Ru. Mix liquid also contains resin binders.
and/or the resin binder itself.
or a part of it, an inner join
and strengthen the bond between the coating and the carbon substrate.
Ru. The reason is that the melted resin or liquid resin is more
Easy to coat permeable components as well as carbon groups
Because it is possible to enter the body and impregnate them
It is. Mitsu liquid is also applied by capillary action.
Prevents the resin from seeping into the gaps between the particles of the fabric composition.
enable. The mix liquid is the solid of the binder system.
A simple addition to the resin binder already present in the body part.
For example, if novolak is present in the solid,
Can dissolve the novolac if present
Like methyl ethyl ketone, it can act
can be evaporated during the curing and carbonization process.
Wear. On the other hand, mix liquid is just an internal carrier.
evaporates during hardening and carbonization even if present as
can be done. In addition, the Mitsu liquid is completely
Frill, like alcohol and furfural,
This compound can function as both a resin-forming agent and a resin-forming agent.
In some cases, some evaporates during heating and the rest remains in the resin binder.
be taken in by. In other cases, the sap is
It can be the fat binder itself. For example, resin bonded
The agent is furfural (usually used with phenol).
), furfuryl alcohol, or
It may be a polymer or a liquid such as a resol.
That's it. mix liquid is a solid resin binder - e.g.
For example, novolac dissolved in a solvent (the solvent part is
(can evaporate in heat) - or high viscosity resins - e.g.
Contains a partially polymerized resol diluted with a solvent.
There is also. Mitsu liquids are also used as gas releasing agents, reformers
It may also contain agents and hardeners. "Binder system" refers to a resin binder,
liquid and, if necessary, gas release agents and modifiers.
and a curing agent. The “gas release agent” forms a liquid phase and is
seeps through the ing and then evaporates, resulting in
This creates small passageways within the coating that release volatile components.
It refers to a substance that can be released. "Modifier" is used in coating in addition to resin binder.
Prior to carbonization, for example, hardenability, electrical properties
quality or physical properties (bending strength, impact strength,
etc.) shall be understood as a substance that improves. “Curing agent” refers to a substance used to copolymerize with a resin.
Or activate the resin to a state where it can polymerize or copolymerize.
It shall be understood as a substance necessary for sexualization. rack
A bridging agent or activating agent falls under this category. Almost
The catalysts required for all polymerization and crosslinking reactions are the same.
Ru. "Carbonaceous filler" means that the C:H ratio is greater than 2:1.
The circumference and size are −100 mesh, and it is a known coal.
As a component of base cement or as a specific carbon system
What is understood as a carbonaceous material that exists as part of a
shall be. The carbonaceous filler may possess reactive groups and
It does not have to be fully carbonized, but the resin binder
Self-polymerization as in the case of is not carried out. Furthermore, charcoal
Essential fillers are methyl ethyl ketone
or insoluble in commonly used solvents such as quinoline.
It is. On the other hand, the resin binder is in an incompletely cured state.
is usually soluble in the solvent. "Carbon additive" is one of the known carbon cements.
As a component or part of a specific carbon system
present, C:H ratio greater than 2:1, -4 to +
Carbon particle aggregates with a particle size range of 100 mesh
and/or carbon material containing carbon fibers
shall be. “Carbon system” refers to the binder system, carbon
Refers to quality additives and carbonaceous fillers, or coating materials.
Refers to product minus RHM. "Carbon cement" is a common resin binder,
Commercial products containing storage liquid, carbonaceous fillers, and hardening agents.
Compatible with commercially available carbonaceous cements or adhesives.
I will do so. In this case, the solid part of the raw material and the liquid
Keep body parts separate to extend lifespan
You can also leave both parts together with premix cement.
It may be integrated as a component. Used in the present invention
If gas-releasing agents and/or modifications are used in the carbon cement,
Additives may be present or may be added.
stomach. In the absence of carbonaceous additives in commercial formulations,
carbon cement for use in the present invention.
It is common to add quality additives. As a modifier, Pituchi is present in some resin binders.
may exist. In this case, hexamethylene
Requires the presence of a suitable curing agent such as tetramine
be. Such hardeners are used as a component of resin binders.
May already be present or may be added.
However, due to the presence of this substance, resin binder and pit
Bridging between pitches or bonding between pitches and carbonaceous filler
or polynuclear aromatic compounds that make up the majority of pitches.
Self-combination of aspirations becomes easier. Pituchi is a graphite precursor
However, in the present invention, black
Leading is not carried out. Therefore, this graphite precursor
is an amorphous carbon precursor that is separated into a resin binder.
be scattered. Pits seep through the coating.
It is also possible to create a gas release passage using a suitable hardener.
resin binder and/or carbon if present.
It may also crosslink with solid fillers. The coating composition used in the present invention has many important aspects.
Constructed to achieve goals. First, the coating composition
Objects flex to accommodate differential contraction and expansion, approx.
800℃ (At this temperature, the coating assembly is slowly heated.
until the product is sufficiently hardened, carbonized, and becomes a hard body)
Adheres strongly to the cathode substrate over temperature. the
After it is applied, the coefficient of thermal expansion of the coating composition is
The coefficient of thermal expansion is very close to that of the cathode substrate. Furthermore, coating
The carbon content of the fabric composition and the type of resin binder are
The total amount of charcoal generated during carbonization must be large.
There is. This creates a large sealed air gap.
and generation of excess gas is minimized. Also, carbonized
The rate of wear of the carbon matrix of the product during operation is
Wear and dissolution of RHM in a mini reduction tank environment
equal to or only slightly greater than the total velocity of
stomach. This allows the coated surface to wear evenly and
RHM is constantly appearing on the coated surface. Set here
"Wear and tear" in this definition refers to both mechanical and chemical mechanisms.
Loss of matter and resultant thinness due to schizophrenia
refers to Pure graphite structure fails in the above points
It is. This is because, for example, internalization of sodium
The anisotropic structure of the graphite matrix results in fairly rapid loss.
It has a stalling rate, and the bond between the atomic layers of graphite material is
This is because they are weak. Achieve these important objectives
In order to
For example, the carbon matrix of the present invention has a flat surface that graphite has.
It has great strength in three dimensions compared to weakness in direction.
It turned out that it was necessary to prepare a First, the total temperature to which the coated cathode block can be exposed is
To obtain coatings with strong adhesion over a wide range
The important thing is that the coating composition is kept at a temperature of approximately 800°C above ambient temperature.
Temperature range up to - In this temperature range, the coating composition
Objects release volatile matter, undergo hardening and carbonization, and become hard.
It exhibits a moderate dimensional change rate during its transformation into a solid.
It is to do so. In this temperature range, the coating composition
Objects become emaciated or compressed, i.e. change in thickness in the vertical direction
the positive line of the cathode block to which it is applied.
In contrast to the dimensional expansion, volumetric contraction occurs. Things to note
As, over this temperature range, the resin binder itself
undergoes considerable expansion and contraction, but during this hardening, the charcoal
During the oxidation stage, the carbon fibers strengthen the coating.
Most effective and minimizes harmful cracks
Limit it to just the cracks. This causes stress
decreases and the difference in expansion coefficient between the coating and the substrate
is allowed. However, once the coating composition carbonizes,
Once it becomes a hard solid, the thermal expansion of this carbonized composition
The coefficient is essentially equal to that of the cathode substrate.
is important. Therefore, the expansion rate (%) of the carbonized composition
For example, over a temperature range of about 800℃ to about 1000℃,
Within about ±0.2 of that of the cathode substrate, preferably about ±
Must be within 0.1. Therefore, apply
The expansion coefficient of the cathode substrate to be maintained is approximately 800℃ to approximately 1000℃.
+0.15% over the temperature range of °C.
The coating is -0.05 to + over the same temperature range.
Expansion coefficient of 0.35%, preferably +0.05 to +0.25%
It is necessary to show that Shrinkage of the cured binder system during carbonization
It is desirable that the size of is as small as possible. child
To achieve this, the carbonaceous resin must be selected appropriately.
stomach. That is, when the carbonaceous resin is used in the present invention,
Destruction of the coating due to carbonization and cathode blots.
or damage to the coating from the cathode substrate.
Coatings that exhibit sufficient shrinkage on the cathode substrate without causing separation.
If a carbonaceous resin is chosen so that a cloth composition can be obtained
good. Vertical details inside the carbonized coating composition
Difficult cracking is an acceptable stress relaxation mechanism.
be. Presence of carbonaceous additives and/or carbonaceous fillers
Being is beneficial. Carbonized binder system and
The contraction and expansion of the coating composition was measured using the following method.
can. Prepare a sample of the composition to be tested and measure 5 cm x
Inside a Teflon-coated mold of 1.27cm x 0.64cm (depth)
spread to This composition is cured, cooled and molded.
Take it out. After the cured product, four test pieces were
Cut each piece into 2.54cm x 0.64cm x 0.64cm), then
They are brought to constant weight at 250℃ in an alumina crucible.
Ru. Place one of the test pieces on a micrometer.
The expansion was measured using a
It was heated from room temperature to 1000°C in a tensiometer. expansion/contraction
Coupling the temperature on a chart recorder as a function of temperature.
Record continuously. Calculate the two values of expansion/deflation.
Ru. One is the length of the initial test piece and the temperature at 1000℃.
the final length after returning to room temperature and the final length after returning to room temperature.
The original thing (this is an overall contraction)
contraction). Chartre
As a check for the coder, mark the specimen after cooling.
It can also be measured using an ichromator. full cycle
Shrinkage or total shrinkage preferably less than about 1.0%
Preferably small. In addition to the above points, carbonization reduces the amount of carbon to about 25% or less.
It is important to use a binder system that provides a
It turned out to be essential. As used herein, charcoal production
The rate is the amount produced by pyrolysis of a unit amount of binder system.
It is defined as the amount of stable carbonaceous residue that forms. each
Thermogravimetric analysis of the seed binder system shows
, the amount of char produced is a function of the aromaticity of the resin structure.
Ru. generally bonded to each other at two or more sites
Usually, the carbon ring remains as charcoal. ladder
The polymer is the most stable and loses only hydrogen.
Produces extremely large amounts of charcoal. Measuring the carbon production rate of the binder system used in the present invention
carbon system (i.e., binder system).
(sum of rubber and carbonaceous filler) is cured for 24 hours to polymerize.
and/or to cause crosslinking, then at 250°C.
volatile matter, polymerization products, and/or
Eliminate unreacted liquid to maintain constant weight. Then, that
The sample was sintered at 1000°C in a non-oxidizing atmosphere and the residual
Measure the weight of the charcoal. Similarly, carbon cis
Measure the amount of carbon in the carbonaceous filler in the carbon system.
of the binder system by subtracting it from the coal content of the system.
Find the charcoal weight. Weight of carbon system at 250℃,
and from the known weight of the carbonaceous filler at 250°C,
The weight of the binder system at 250°C can be calculated.
The charcoal production rate of the binder system is then determined by
Stem charcoal weight and binder system at 250°C
Calculate as a percentage from the weight of According to experiments,
Various binder systems exhibiting charcoal production rates greater than approximately 25%
Cortein can be tolerated by hardening and carbonization.
Binder system with 8% charcoal production
gave unacceptable carbon matrix by carbonization. 50
% or more is preferred. Durable coating composition in aluminum tank environment
What is required is to produce carbonized carbon in the above environment
The system wear rate is close to that of RHM.
be. As RHM moves away from coating
Therefore, the RHM carbon matrix has a similar rate or
depletes at a slightly faster rate than the RHM
will be exposed to the tank environment. In this way,
Coated cathode surface is essentially constant with respect to RHM content
The operation of the tank on the scale of constancy is changed.
be good. Too much effort to provide RHM coated cathode
Attrition and/or particle-to-particle attacks
because the RHM or the carbon host is faster than the other.
rapid surface deterioration due to rapid wear and tear.
Similarly, there is a lot of RHM locally on the surface of the coated cathode, and the bonding strength
Places where there is a shortage of RHM or places where there is a lot of carbon and a lack of RHM
There has occurred. In the present invention, RHM and carbon matrix are dissolved.
Cords that intertwine or wear out at approximately the same rate
The above problems can be overcome by providing
get dressed With respect to the present invention, related to the heating of carbonaceous bodies
Clarify or differentiate the meanings of “carbonization” and “graphitization”
It is important to do so. Carbonization usually converts carbonaceous bodies into
Unitary form for the purpose of removing volatile matter
(unitary form) or heated in granular form and gradually C:
By increasing the H ratio and gradually reducing hydrogen,
It is done. In the carbonization process, the temperature is gradually raised.
to prevent the volatilization of decomposition products, etc., to avoid foam formation.
The amount of cracks is slowly generated to prevent the formation of large cracks.
To avoid volumetric shrinkage (occurs at some point during the process)
Progress gradually. Curing occurs at temperatures up to approximately 250°C.
However, the carbonization temperature is usually about 250° to approx.
Over 1000℃. However, temperatures up to 1600℃ or higher are used.
You can also be there. Continue carbonization until approximately 1000℃ or higher
However, carbonization of the carbonaceous material present is essential.
The process ends at approximately 800℃, and the resin binder carbonizes and fills.
Combines filler materials and RHM into durable structures.
Ru. Hardening at the cut stage and carbonization at the initial stage are usually performed using gas
or in an oil-heated conventional radiant or convection oven;
Heat supply to the carbon can be achieved through indirect heat transfer or direct contact with the flame.
Do it by touching and implement it. At some point, an example
For example, at temperatures above about 250°C, carbonaceous materials are sufficiently conductive.
and allows resistance heating if desired.
Become. Of note, the coating composition here
It can be applied to any desired thickness and smooth surface.
It is preferably in the form of a paste with commercial properties. child
Gently heat the material to about 250℃ to cause polymerization and
and/or cause crosslinking and further evaporate volatile components,
Let it harden. Already at a temperature of about 250°C, the coating composition
reaches a thermosetting state and becomes a relatively hard object.
Ru. Carbonization at temperatures above 250°C results in this
is mainly composed of non-graphitized carbon, RHM, carbon
Hard matrix containing elemental additives and carbonaceous fillers
Changes to It contains only this material and a pitch binder, and has no crosslinking agent or
is distinguishable from prior art materials that do not have polymerizing agents.
It takes. By itself, pitucci can cause crosslinking or polymerization.
However, it actually becomes liquid between about 50℃ and about 500℃.
Pass through a "plastic" state or zone. this
In the temperature range, a fairly large expansion occurs and then
The carbonaceous material solidifies (and shrinks) to become hard coke.
Becomes a solid. On the other hand, the coating composition is
Polymerization and/or crosslinking may begin at low temperatures.
from about 250℃ depending on curing time and coating thickness.
It hardens until it reaches a low temperature and becomes a relatively hard resin-like material.
and then gradually hardens through carbonization.
go. The entire heating cycle for carbonization takes too long.
Ru. Normal carbonization eliminates volatile matter and heat content.
Volatile reaction products produced in the solution are removed. deer
and the crystallographic structure of the carbonaceous additive or carbonaceous filler.
No major changes occurred in the structure, and the carbonized resin changed considerably.
Combine the amount of graphite material or graphite microcrystal-containing material
Although it may be, it is still amorphous.
It looks like Graphitization is easily distinguished from carbonization. Sunawa
However, graphitization requires significantly higher temperatures and longer times.
The atomic structure changes rapidly and is easily observed.
I can understand it. In graphitization, the temperature used is approximately
The temperature ranges from slightly higher than 2000℃ to 3000℃. representative
The temperature is approximately 2400℃ or 2500℃ to 3000℃.
℃, but the reason is that these temperatures are higher than normal.
This is because it leads to quality graphite. Rather than heating
It takes a long time, typically about two weeks. No heating
Passing an electric current directly through ordinary carbon in an oxidizing atmosphere
and internally binds carbon due to its own electrical resistance.
Heat directly. This method is used in carbonization.
This is different from traditional furnace and heating methods. graphite
This is a major change in the amorphous or partially graphite internal structure.
The atomic arrangement of graphite crystals is
It's done. As is well known, the graphite structure is a dense packing.
It has a graphite structure with a layered structure and a specific orientation.
Indicates a column. In general, graphitization is performed using a well-known graphite precursor.
This can only be done using quality (e.g. pitch).
Ru. Internal structure of graphite and non-graphitic or amorphous carbon
To show the difference, d₀₀₂Dimensions and L_cdimensions are useful
Ru. "L_c” dimensions are in the “c” direction (perpendicular to the bottom)
applied to the size of crystals or microcrystals in
, ``d<sub>002</sub>” dimensions are interlayer voids. These dimensions
The method is usually measured by X-ray diffraction techniques. R·
In the definition of R.E.Franklin
According to d<sub>002</sub>is 3.44Å, and L<sub>c</sub>but
It is 3.35 Å. [Acta Crystallographica, 3rd
Volume, page 107, 1950; Proceedings of the
Royal Society of London, Volume A209, Page 196,
1951; Acta Chrystallographica, Volume 4, No.
250 pages, 1951] In the process of graphitization, before graphite
The amorphous structure of precursor carbon transforms into the crystalline structure of graphite.
Ru. This change is L<sub>c</sub>Increase in dimension and d<sub>002</sub>Dimension reduction
It is shown by. For amorphous carbon, L<sub>c</sub>Dimensions are approximately 10
It is usually in the range of ~100Å, but most
In which graphite L<sub>c</sub>dimensions or larger than approximately 350 or 400Å
It is typically 1000 Å from 400 Å onwards.
There is also something called ``essentially graphitic structure'';
If L_cis about 100 Å to about 350 or 400 Å. child
The structure of
Structurally, the graphite described above has a similar atomic arrangement and
shape, but the orientation of consecutive atomic planes is
The X-ray diffraction pattern is different from that of graphite.
are somewhat different. Both graphite structures, d₀₀₂size
is smaller than about 3.4 Å. Generally, graphitization is about 2000
℃ to about 2400℃, a “semigraphitic” structure is produced.
Easy to do. On the other hand, if carried out at a temperature higher than 2400℃,
It tends to produce a "normal" graphitic structure. Carbonaceous core for aluminum tank cathode according to the present invention
of possible methods of manufacturing
For one, granular graphite is used as a filler, and a binder and
and other ingredients. Spread these mixtures,
Hardens and carbonizes. This carbonized carbonaceous material is black.
Although it may contain some lead, the graphite
Not more combined, but rather black from the filler
Lead particles and binders and/or carbonaceous fillers
Contains amorphous carbon produced from carrying out the invention
The important thing is that the carbonized coate of the cathode
The material is made of a binder that does not turn into graphite.
This improves electrical and thermal conductivity on the carbon-RHM surface.
temperature, expansion coefficient, wear rate, and stability.
It means that it has value. In general, boration of elements in groups 1 to 3 of the periodic table
All substances, carbides, silicides, and nitrides have high melting properties.
point, high hardness, good electrical and thermal conductivity,
Aluminum is moistened by molten aluminum.
and has resistance to alumina-cryolite melts.
Two. Relatively low cost and melting of oxyfluoride
High resistance to aluminum and molten aluminum
So, TiB₂is the preferred RHM. RHM granularity
is less than a micron to about 10 mesh, preferably micron.
less than or equal to about -100 meters, most preferably
Approximately -325 meshes is suitable. TiB₂or oxygen impurity at the interparticle boundaries between RHM crystals.
The first thing to do is to make objects more susceptible to attack by separating them.
generally considered. Also, TiB₂in the individual crystals of
Transfer of dissolved oxygen to intercrystalline boundaries
Also, the normal operating temperature of the aluminum tank, i.e. 1000
This is possible by using the diffusion method at around ℃.
it is conceivable that. Therefore, oxygen impurities initially
TiB₂Regardless of whether they separate at the crystal surface,
Move to intercrystalline boundaries and expose those boundaries to attack
It is possible to make it easier to All of the intercrystalline boundaries
When a part is attacked, TiB₂Crystals are lost. According to what is currently known, TiB₂single crystal of
TiB₂bicystal, open cluster TiB₂Conclusion
TiB crystals and/or crushed and ground TiB₂crystal is carbon
in an aluminum bath when in close contact with the parent body.
Even after long-term exposure to baths and molten aluminum,
Will not crack or collapse. In this specification,
Said TiB₂The term "single crystal" refers to all forms of
shall be included. After all, it is important to understand
The explanation is mainly TiB₂is made about, but other
RHM materials may also be considered. all these particles
A common feature is that these particles usually have two or more
The free crystal surface exposed above the intergrain boundaries
It has more planes or crystal cracks. obey
The binder system is applied to the crystal surface or fracture surface.
By combining almost all TiB₂crystal
You can peck at it. Smaller open clusters
TiB₂A carbonaceous binder system is contained within the crystal.
TiB₂The boundaries between crystal grains
Even if attacked by a bath, these TiB₂the crystal is still
retained during coating for binder as
Ru. This phenomenon is caused by crushed pieces in the carbonized coating.
It was observed that TiB₂shell-like or glass-like
Since there is a tendency to fracture, the fragments cut the crystal planes.
Surfaces with cut surfaces and bonding agent systems
form a strong bond with Carbon and carbon on the surface of the cathode made according to the present invention
TiB₂Both components slowly dissolve or corrode, and the
For new TiB₂Aluminum crystals constantly melt
It looks like it's touching. TiB₂, both carbon,
Various chemical mechanisms are used until saturation concentration is reached.
and dissolve it in metal aluminum in a tank. deer
However, even after the saturation point, these substances remain as insoluble particles.
Alternatively, they may exist as compounds containing them.
TiB₂and the rate at which carbon is lost from the cathode surface is
Temperature, aluminum, bath, and mud motion,
It depends on various factors such as
It will be done. TiB₂Some of the particles are completely attached to the aluminum
carried away in the aluminum before melting.
It is considered. TiB in metal aluminum₂dark
The solubility is usually only slightly lower than the solubility at the tank operating temperature.
I know that it is only expensive. The carbon loss rate is
is an important factor in wet cathode cells containing RHM.
Ru. This is because RHM grains in the cathode coating
This is because carbon is used to bond children. carbon
When the loss rate becomes excessive, TiB in the carbon matrix₂grain
The lower part of the cathode is gone and TiB is removed from the cathode surface.₂loss of
increases. If the carbon loss is too low, the cathode surface
TiB₂There are areas where the particle concentration decreases locally,
Then, the moisture caused by aluminum is reduced in that area.
Do a little. TiB preferred for use in the present invention₂is typically
−325 mesh. TiB₂Chita
Carbon reduction for boron, boron oxides and carbides
(carbothermic reduction)
The individual particles produced are usually single crystals.
Meet the requirements. This means that PPG Industrial
Rice licensed to Hoekje in Leeds
Made using the plasma method described in National Patent No. 4282195.
TiB₂This also applies to . arc melt
TiB by fusion method₂When manufacturing , each is relatively large.
Polycrystals of crystals are usually formed. obey
When crushed into −20 mesh pieces, the short grains
Particles with only child boundaries are commonly generated. arc
Molten TiB₂Crush the lump to -325 mesh
TiB₂When powder is made, each of the resulting particles is the original crystal.
each smaller, so each particle is smaller than that
Large crystals (or, for example, two or three crystals)
It consists of fragments of crystals (bound together at intercrystalline boundaries).
Therefore, only a few crystals are part of the binder system.
are discrete, and some intercrystalline boundaries of these crystals are
Even if it is completely dissolved by the bath, the fracture will be dispersed.
There are very few crystals. TiB obtained by carbon reduction of powder₂is normal,
-325 mesh without destroying individual crystals too much
It consists of materials that can be easily crushed. this
When viewed under a scanning electron microscope, the substance appears as small single crystals.
crystal, open cluster TiB₂Single crystal and crushed TiB₂
It is made of single crystal. In the coating disclosed herein
TiB₂In cases where there is no problem in replacing RHM with other RHM substances,
There is a case. However, when replacing, please add to the coating composition.
Make appropriate changes to reduce the RHM exposure resulting from the substitution.
Differences in wettability, surface area, particle size, porosity and solubility
solve. Add sufficient amount of RHM to the coating composition
, the wettability of the aluminum is sufficient, and the heat
The expansion unbalance is minimized and the dissolution rate of RHM is
less than the loss rate of the carbon matrix of the coating.
Ru. The description of the invention is based on TiB as a preferred RHM.₂
Although the focus is on the use of
(e.g., ZrB₂, RHM material
mixtures) may be used. In coating composition
Adding a sufficient amount of RHM to the water will result in sufficient wettability.
can get. Generally, from about 10 to about
90% by weight, preferably about 20 to about 70% by weight
be able to. Wettability is low even at concentrations below approximately 10%.
It turns out that better results are obtained with 20
% or more, with a preferred range of about 35 to about 60%.
be. The resin binder of the present invention passes the aforementioned criteria.
Anything is fine. Typical resins that can be used
Examples include phenols, furans, and polyphenylenes.
and heterocyclic resins, as well as epoxy, silicon
Examples of resins include carbon, alkyd, and polyimide resins.
be able to. Examples of usable phenolic resins
is phenol formaldehyde, phenol formaldehyde
Cetaldehyde, phenol-furfural, m
-cresol formaldehyde and resorcinol
There are formaldehyde and formaldehyde resins. usable
As an epoxy resin, bisphenol A jig
Lycidyl ether, tetrachlorobisphenol
diglycidyl ether of A, di-glycidyl ether of resorcinol
Glycidyl ether, etc., and various epoxyno
There is boratsuku. Preferred epoxy resins include each
glycidyl ethers of seed phenols.
Sydyl ethers, especially dihydric phenols, are
Products obtained by reacting with lohydrin, such as bis
Phenol diglycidyl ether and various other
There is epoxy novolac. available silicone
Polymers include methylsiloxane polymers and mixtures.
Methylphenylsiloxane polymers, e.g.
Chylsiloxane polymer, phenylmethylsiloxa
polymer, phenylmethylsiloxane and dimethyl
Copolymers of siloxane and diphenylsiloxane
There is a copolymer of siloxane and dimethylsiloxane. multiple
An example of a ring resin is polybenzimidazole.
ole, polyquinoxaline and pyrone. well known
Certain alkyds, especially phenol formalde
Uses those modified with hydride and polyimide resins.
I can be there. Phenol resin and furan tree
Fats are a preferred class of fats due to their relatively low cost.
It is a resin. Furan resin is an excellent resin binder for the present invention.
It can be used advantageously. Furan resin polymerization catalyst and
Various acids and bases are used for this purpose, but furan is
When it can be copolymerized with other resins without a catalyst, this
Acid or base catalysts may not be used. Appropriate
Acid catalysts include various inorganic and organic acids, e.g.
Hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, benzenesulfonic acid,
Toluenesulfonic acid, naphthalenesulfonic acid,
Leic acid, oxalic acid, malonic acid, phthalic acid, lactic acid,
There is also citric acid. This type of catalyst includes organic
Acid anhydrides, such as maleic anhydride and phthalate
Also includes acid anhydrides. of conventional acid catalysts available
Examples also include urea, thiourea and substituted ureas (meth
mineral acid salts of lurea, phenyl urea, etc.), ethanol
amines (mono-, di-, and triethanolamines)
mineral acid salts of amines (mine), as well as amines (methylamine,
trimethylamine, aniline, benzylamine,
There are mineral acid salts of morpholine, etc.). preferred acid
The catalyst has a Ka value of at least 10^-3It is. Suitable basic catalysts include alkali metal hydroxides.
substances (e.g. lithium hydroxide, sodium hydroxide,
potassium hydroxide, etc.) and alkaline earth gold
hydroxides (e.g. magnesium hydroxide, etc.)
). Other usable basic catalysts
For example, there are amine catalysts, and primary amines
(ethylamine, propylamine, etc.), secondary
Amines (diisopropylamine, dimethylamine
), tertiary amine (triisobutylamine, etc.), tertiary amine (triisobutylamine, etc.),
amine, triethylamine, etc.).
Ru. Further examples of basic catalysts that can be used include:
Alkali metal hydroxides and alkaline earth metal waters
Mixtures with oxides (e.g. sodium hydroxide and
mixture with calcium hydroxide). this kind of
The mixture has an unexpectedly high carbon production rate
A thermosetting binder is provided. Appropriate amount of catalyst or hard
Depending on the type of resin binder you choose,
added to. Determine the type and amount of hardening agent to add.
This technology is also included in this technology. "Acid-cured furan resin" means the following resin:
Ru. i.e. homopolymerization of frifuryl alcohol
furfuryl alcohol, a homopolymer of furfuryl alcohol
cross-linked with Ral, furfuryl alcohol and
Formaldehyde copolymer, furfuryl alcohol
copolymer of alcohol and phenol, and its structure
Crab has a furan ring, and by adding an acid catalyst, the final
A monomeric substance that can be hardened into a hard body. Resinization of compositions containing curing agents depends on the hydrogen ion concentration.
As is well known, it is accelerated by heating. acid
This reaction, which occurs with the addition of a catalyst, is exothermic.
Therefore, care must be taken in selecting the catalyst and the amount added.
Ru. Otherwise, resinization will proceed too quickly and the
product becomes unusable. For this purpose, inorganic acids (salts)
acids, sulfuric acid, phosphoric acid, chromic acid, etc.) are commonly used.
Not possible. On the other hand, inorganic acid salts (zinc chloride, sodium hydrogen sulfate)
Thorium, mercury chloride, etc.) are commonly used.
In addition, latent acid catalysts generate the necessary acid only during heating.
media (maleic anhydride, phthalic anhydride, etc.)
) is also similar. In general, the desired properties in acid-cured furan resin products
Organic compounds are usually preferred. aromatic
In addition to sulfonic acids, aromatic sulfonochlorides
(benzenesulfonochloride, paraacetyl bene
aromatic sulfonochloride, etc.), aromatic sulfonochloride, etc.)
Aliphatic amine salts of fonic acid (including ammonium salts)
nothing. Ammonium paratoluene sulfonate, di
Methylaminobenzene sulfonate, diethyla
Minotoluene sulfonate, ammonium benzene
sulfonates and disulfonates, ammonium
Muphenol sulfonate, ammonium naphtha
Rensulfonate and disulfonate, ammonia
Umanthracene sulfonate and disulfone
ammonium sulfaninate, etc.), aromatic
Aromatic amine salts of aromatic sulfonic acids (benzenesulfonic acid)
Aniline salt of fonic acid, paratoluenesulfonic acid
Aniline salt, pyridine of phenolsulfonic acid
salts, etc.), organic salts of strong inorganic acids (Glyoxalus
sulfate, etc.), metal salts of chlorosulfonic acid
(sodium chlorosulfonate, chlorosulfone
potassium acids, etc.), aliphatic and aromatic inorganic strong acids
family salts (triethanolamine chloride, anili
ammonium hydrochloride, ammonium sulfamate, pyridine
sulfate, pyridine bisulfate,
niline sulfate, etc.), sulfanilic acid
Amine salts (aniline sulfanilate, pyridine
ferric salts of sulfonic acids (sulfonates, etc.)
Erythmic trichlorobenzene, etc.), acid anhydrides
(phosphoric anhydride, maleic anhydride, etc.), Arcanth
Ammonium salt of sulfonic acid (ammonium ethane
sulfonates, etc.), ferric salts of sulfonic acids
(Felitsuku benzene sulfonate, Felitsuku benzene sulfonate, Felitsuku benzene sulfonate,
toluenesulfonate, etc.), as well as organic substitutions
Ammonium salts of inorganic acids (ammonium ethylphosate)
sulfate, etc.) are used as catalysts for furan resins.
I've been bored. Suitable furan binder containing alkaline catalyst
as furfural + phenol, furfural
furfuryl alcohol + ketone, and furfuryl alcohol + alcohol
There is dehyde + amine. Furan binder optionally
It may also be used as a binder in a mixed form. This conclusion
The mixture can be mixed with carbon filler. join
Coal tarpit as a modifying component in agent systems
There may be pitches such as chi. These bits
Is the high-boiling concentrated aromatic system obtained from
It is often found as an impurity in fillers obtained from
Ru. Among the furan binders suitable for use in the present invention are
The following (containing a suitable catalyst) are available as follows:
Ru. 1 Furfural phenol As a specific example, furfural phenol
Lefural + phenol. 2 Furfleur + Ketone As a specific example, furfur
Furfural + Acetone or Furfural + Siku
Lohexanone. 3 Furfuryl alcohol + aldehyde + amine
As a specific example, furfuryl alcohol + hol
Mialdehyde + urea. It is relatively fluid at room temperature and has a suitable carbon production rate.
Furfural linkages suitable for use in the present invention
An example of an agent is coal with a softening point higher than 100℃.
50-75% by weight of tarpitz, phenol, and
lohexanone and formula CH₃-CO-R (here R is carbon
is a hydrocarbon group with a prime number of 2 to 4)
one substance selected from the group consisting of compounds and
Monomeric polymerizable thermosetting dispersion consisting of fural
There is a mixture consisting of 50-25% by weight of agent and catalyst.
Ru. The hydrocarbon group in the above formula can be saturated or unsaturated.
It may also be a straight chain or a branched chain. This binder
Effective by adding appropriate amount of RHM and carbonaceous filler
A coating composition can be obtained. Co in the dispersant
Time and temperature required to melt tar tarpitz
is the softening point of coal tar pitch, the total
amount, as well as the relative amounts of different dispersants used.
depends on. Heat is applied to prevent premature polymerization of the binder.
We must avoid overdoing it. Coulter in dispersant
Parameters of time and temperature required to melt Lupituchi
Although it is not possible to describe meters in general,
This is an easy decision for a business owner. This type of coating set
In the case of composites, Pituchi is used as a modifier for the binder.
The ability to have a desirable high charcoal production rate without
Acts as an ingredient. Generally speaking, phenol is the first dispersant component.
If there are two components, furfural vs. phenol.
Preferably, the molar ratio is between 0.5 and 2:1. Siku
Lohexanone, a methyl aliquot of the above formula
A ketone, or a mixture thereof, is the second dispersant component.
furfural vs. cyclohexa, if any
Non, methyl aliphatate ketone, or
It is preferred that the molar ratio of the mixture is 1 to 2:1.
Delicious. currently commercially available materials that can be used in the present invention.
The product name of the furan binder for lukali-catalyzed polymerization is
“QX-362” Quaker Oats Company
- (Quaker Oats Company) product. child
The main components of the binder are furfural and cyclohexano
and some furfuryl alcohol is also present.
It is currently believed that this may be the case. A group of furfuryl resins deemed suitable for the present invention
is maleic acid or maleic anhydride mixed with ethylene
React with polyhydroxy compounds like Recall
It is a furfuryl alcohol copolymer obtained by
Ru. This stuff is ethylenically unsaturated, polycarboxylic
form a phosphoric acid ester prepolymer. This S
The terprepolymer is then added to furfuryl alcohol.
Copolymerized with furfuryl alcohol copolymer
arise. Furfuryl alcohol copolymer compared
Low volatility, ease of storage, and release of water during curing
Low volume, resistance to excessive shrinkage and comparison
It is useful because of its properties such as short curing reaction.
be. These copolymers have other properties, namely hardening
The present invention is also very flexible.
It is very suitable for use. Commercially available carbon cell such as UCARC-34 mentioned below
There are many types of ingredients in addition to those mentioned as ingredients of ment.
In the present invention, the novolak resin is used as the basic resin binder.
It can be used as What is “Novolatsk”?
It is a condensate of a phenol compound and an aldehyde.
The condensation is usually a phenol compound in the presence of an acid catalyst.
Do this by using excess moles of a substance. Generate novolak
In the resin, methyl
There are practically no phenol groups, and the fraction of phenolic compounds is
The children are linked together by methylene groups. Fueno
The ring compound may be a phenol or a benzene ring.
If one or more attached hydrogens are replaced by a substituent
It may also be phenol. the latter phenol
Examples include cresol, phenylphenol,
3,5-dialkylphenol, chlorophenol
resorcinol, hydroquinone, xylenol
There are many examples. Phenol compound is naphthyl
or hydroxyphenanthrene or having a condensed ring
Even if other hydroxyl derivatives of the compound
good. It should be noted that novolak resin
It does not heat cure by itself. Novolac resin is hard
oxidizing agent (formaldehyde + basic catalyst, hexame
Tylenetetramine, paraformaldehyde + base
catalyst, ethylenediamine formaldehyde, etc.
hardens in the presence of A meltable novolac with a suitable aldehyde
Anything that can be polymerized is considered within the scope of the present invention.
It can be used in many ways. To put it another way, Noboratsu
Two or more molecules that can be polymerized and/or crosslinked
It has parts of What kind of things can happen if we leave this limitation?
Boracs can also be used, some of which include modified novo
lactate, that is, non-phenolic compounds are also included in the molecule.
such as diphenyl oxide or bisphenyl oxide.
Enol A modified phenol formaldehyde novo
Also includes racks. Usually novolac has a number average molecular weight of about 500 to about 1200.
have a quantity. However, in exceptional cases, this molecular weight is
It can be as small as 300 or as high as 2000 or more.
be. Unmodified phenol formaldehyde novola
Tsuku has a number average molecular weight of about 500 to about 600.
is normal, and most commercially available products fall within this range.
Ru. In the present invention, a molecular weight of about 500 to about 1200 is used.
It is preferable to use a novolak having the following properties. very
When using a low molecular weight novolak, the novolak
The temperature at which it softens and becomes sticky is usually relatively low.
It is. To make a mixture of pituti and novolatsk, dry
Mixing method or heating melting method to obtain a homogeneous mixture
Any conventional method may be used. mentioned above
As mentioned above, various pitches can be used for this purpose.
Ru. In addition to novolac phenolic resin, resol
Uses also fall within the scope of the invention. Resol resins are phenolic under alkaline conditions.
most commonly produced by the condensation of alcohols and aldehydes.
It will be done. Resol and Novolac differ in the following points:
Ru. In other words, in the case of resols, polynuclear methylol substitution
Phenol is produced as an intermediate. alkalinity
The phenolic material is reacted with excess aldehyde in the catalyst.
Accordingly, resol is manufactured. Phenol and hol
The resol made by condensation of maldehyde is
There is a strong possibility that an intermediate with the following structural formula will be lost.
Strong against For a typical synthesis, 1 mol under alkaline conditions.
of phenol and 1.5 mol of formaldehyde are added.
Heat it to make resol. Phenol and formua are used to make resol resin.
by condensation of rudehydes or, more generally, aromatic
having two or three reactive hydrogen positions on the group ring
phenol compound to aldehyde or phenol
Aldehyde-generating ability that can undergo alcohol-aldehyde condensation
React with a compound. An example of phenol is
Phenol, cresol, xylenol, alkyl
Luphenol (ethylphenol, butylphenol)
ol, nonylphenol, dodecylphenol,
Isopropylmethoxyphenol, chlorophenol
resorcinol, hydroquinone, naphthol
2,2-bis(p-hydroxyphenyl)
lopane, etc.) and mixtures of these phenols.
There are things. The benzene ring allows for the substitution of large aliphatic groups.
If this occurs, the effectiveness of the present invention will be reduced. Because this
These substituents disappear upon heating, resulting in char formation.
This is because the rate may decrease and the volatile content may increase.
be. Examples of aldehydes include formaldehyde
paraformaldehyde, acetaldehyde,
Acrolein, crotonaldehyde, furfura
There are many examples. As an example of an aldehyde generator
There is hexamethylenetetramine. acetone
Ketones such as are also condensed with phenolic compounds.
Phenolic resins can be produced. The condensation of phenol and aldehyde occurs in sodium carbonate.
um, sodium acetate, sodium hydroxide, hydroxide
In the presence of alkaline reagents such as ammonium chloride
It is done. After the reaction is complete, add water and other ingredients as desired.
volatiles are removed and the catalyst is neutralized. Resol resins are called thermosetting resins. sand
That is, under heat load, this resin polymerizes sequentially and the final
It becomes insoluble, unmeltable and completely hardens. Book
For purposes of invention, curable phenolic resins are
It is assumed that polymerization has not progressed to the extent that it becomes
Ru. Furfuryl alcohol is used as a mix liquid.
Can be used in enolic carbonaceous binder
Ru. When the phenolic resin hardens, this product
It is thought that it reacts with enol resin, and this resin
acts as a modifier for furfuryl alcohol
It is preferable to use . Because this mix liquid
A strong bond is obtained by using
Binding cannot be obtained using other mixers.
This is because we know that there is no such thing. Therefore, an example
For example, use furfural instead of furfuryl alcohol.
A coating composition was prepared using
If the binding force is furfuryl alcohol
This is only half the case. The true end goal is essentially RHM and carbon.
The purpose of the binder system is to obtain a distinct surface layer.
These materials easily decompose and produce a high rate of residual carbon.
Must. These compounds are used as resin binders.
Minutes as part of carbon cement or carbon system
from about 1% to about 40% of the coating composition, whether as
need to be occupied. The resin itself is coated at maximum
It can represent about 50% or more by weight of the composition.
Higher resin concentrations are possible, but
Hardening and carbonization cycles with little benefit
may be long. The carbon system is a cathodic group
About 10 to about 90% of the composition applied to the body, preferably
about 30 to about 80%, most preferably about 40 to about 65%.
It is necessary to Carbon and phenolic resin or thermosetting of appropriate particle size
a suitable mixture with a synthetic resin binder, or alternatively
Commercially available compositions can be used. of the coating composition
The mix liquid components have a suitable evaporation and curing rate.
Approximately 2 to 40% by weight is sufficient, but approximately 5 to 40% by weight
About 25% is preferred to obtain a workable consistency.
The coating composition has workability and can be easily spread with a trowel.
It is desirable to obtain. If there is not enough liquid, the composition will dry out.
It dries and becomes difficult to spread, while too much liquid causes it to harden and spread.
baking becomes difficult. Resin binder during mixing, curing, and carbonization of coating compositions
Various modifiers exist for the purpose of modifying the properties of
It's okay. These modifiers are commonly used in coating compositions.
It can be from 0 to about 10% by weight. phenol
Suitable as a modifier for formaldehyde resins
For example, rosin, aniline, copolymer,
resin "alloys", etc. rosin change
Polymer phenolic resins have important characteristics such as solubility, viscosity, and drying properties.
It has both the necessary properties. Used in coating compositions
Well known methods of making phenolic resins include phenolic
Heating and mixing formaldehyde condensate with rosin
Contains steps to The condensation used in this case
The substance is converted into alkylphenol by alkaline condensation.
Preferably, it is made from. To make aniline-modified phenolic resin,
The intermediate condensate of norformaldehyde is converted into aniline or
is an aniline derivative, which can be synthesized by co-condensation or by phenol
Formaldehyde condensate and aniline formal
Treated by mixing with dehyde condensate. Anili
Modified phenolic resins have particularly good electrical properties.
has. Phenol resin is chlorinated phenol,
Nitromethane and even organosilicon compounds (e.g.
copolymerization with materials such as siloxanes)
Can be done. Treatment of phenol formaldehyde intermediate condensate
As part of the substances used in
ether resins, ethylene oxide polymers,
hydrogen oxide, ketone, methylolaniline hydrochloride,
Polyvalent salts of hexanoic acid, stannous chloride, and terpe
There is a phenol product. Furthermore, mixing various resin substances and phenolic resin
You can also make things. More common resin “mixtures”
Examples of "alloys" include phenolic resin and
Epoxy resin, ketone-aldehyde condensate, Mela
mineral and urea resins, natural and synthetic rubber, polyvinyl
luchloride and polyvinyl acetal resin
There is a combination of Such modifications improve the binder system of coating compositions.
It is not at all possible to carry out extensive stem modification.
Ru. For example, if phenol is mixed with metacresol,
Frog is soluble in alcohol and has a short drying time.
Produces resin. Such modifications may occur under certain circumstances or
This may be useful when curing time is limited.
Replace phenol with meta-alkyl phenol
more rubbery, more flexible but with less tensile strength.
This results in a resin with a reduced quality. Phenol replaced with phenol
Nols (e.g., paratertiary butylphenol)
When replaced with olefin, an oil-soluble resin is produced. one
However, phenol is induced by naphthalene and anthracene.
The properties of phenol even if it is replaced with phenol
does not change significantly, but the binder system using pitch
In the stem, compatibility with pitch becomes greater. Ho
Higher grade lumaldehyde like acetalhyde
When replaced with aldehyde, the resin becomes oil-soluble.
Ru. Glyse to phenol formaldehyde resol
Adding rolls will affect the binder system used.
It acts as a plasticizer inside. On the other hand, before adding the acid catalyst,
Furfuryl with anthracene oil as a stabilizer
Can be added to alcohol. This stabilization
Control of polymerization rate in the presence of acid catalysts
It helps. Certain specific mixtures are noteworthy. for example,
Phenol - Phenol modified with furfuryl resin
formaldehyde is a flat plasticity
- has a plasticity curve, and has a plasticity curve.
through the rubbery state shown by formaldehyde.
Don't miss it. Therefore, phenol formaldehyde
and phenol-furfuryl are suitable.
Ru. This mixture has excellent impact resistance, chemical resistance, high
Fast curing at high temperatures as well as great acceptance of fillers.
have capacity. phenol formaldehyde and
Mixtures with certain thermoplastics may cause bonding to metals.
(e.g. for use with metal cathode substrates)
(resin that can be considered). phenol
Formaldehyde to butadiene/acrylonitrile
When mixed with rubber copolymer rubber, the impact resistance is improved.
It will be done. On the other hand, resorcinol formaldehyde tree
When mixed with fat, the reaction rate is faster and the curing temperature is lower.
It becomes. However, these resins cannot be used in the present invention.
It's too expensive to do so. Pitch often contains modifiers or
As a binder, up to 50% or up to 75% (binder
concentration (if present as a functional component of the system)
exists in When present as a modifier itself
Pituchi can be added to the coating composition at a concentration of up to 10% by weight.
can exist in degrees. RHM and binder system (filler itself)
(sometimes containing carbon), adding particulate carbon
is desirable. Amorphous or graphitic particulate carbon
to the extent that it is present in the commercially available carbon cement mentioned above.
This is often the case. Amorphous or graphitic particulate carbon
in the form of fine powder, coarse particles, or mixtures thereof.
May be added to. Carbonaceous fillers can be used in specified carbon systems or commercially available carbon.
As a component of cement or commercially available carbon cement
It is highly desirable to be present as an additive to
Yes. These carbonaceous fillers are -100 mesh,
Preferably -325 mesh, carbon fine powder,
Graphite powder, crushed coke, crushed graphite, carbon block
It can include racks, etc. These fine powders
The presence of powder improves the packing density of the particles and
The fat-forming liquid is wicked up and carbonized to form a dense and highly
A carbon matrix bonded to is produced. The carbonaceous filler as a fine powder is included in the coating composition.
It must account for about 1 to about 60%, and about 10 to about 40%
is preferred. If carbonaceous additives or agglomerates are present,
Its size must be between -4 and +100 meshes.
Bye. Preferably it is -8 to +20 meshes.
These coarse aggregates are clearly microscopic cracks.
Provides cracking, helps release volatile substances, and reduces shrinkage.
This contributes to a high coal production rate. Aggregates and/or
Or the carbonaceous filler in the form of fibers can be
It should account for about 0 to about 70% of the composition, and about 5 to about
15% is preferred. As mentioned above, carbon dioxide is used as a crack preventive agent.
Preferably, fibers are added to the coating composition. carbon fiber
When using fibers, some changes in the coating composition may be required.
It was seen. When using carbon fiber, use pitch
Precursors, organic fiber precursors (e.g. polyacrylate)
made from lyronitrile) or rayon
It is preferable that Pituchi Seni is pretty
It is preferred because it is inexpensive. The fiber weight is 0 to about 10% by weight relative to the coating composition.
%, preferably about 0.05 to about 1.0%,
More preferably 0.05 to about 0.5%. but,
Concentrations higher than about 10% will be relatively expensive, so
There are no noticeable profits. Approximately 0.16~1.27
Carbon fibers with a length of cm are preferred. The short fibers are
Allows for easy mixing and application and can be used in high concentrations
Ru. Parallel helix bonded with a substance soluble in mixtures
Particularly preferred are bonded fibers consisting of a group of fibers. Why?
This fiber is most easily mixed with the binder system.
Because it matches. The orientation of the fibers can vary;
fibers can be used as a necessary component of coating compositions.
This facilitates the application work of the composition. It is also possible to modify the carbon filler used. child
In this regard, adding a number of modifiers to the filler
Can be done. For example, adding silica to carbonaceous filler
can impart non-sintering properties to the binder system.
can. However, in general, inorganic fillers may be used according to the present invention.
Makes the resin binder harder and reduces charcoal formation during
reduce the rate. A gas releasing agent is suitably added to the coating composition.
and the formation of bubbles and/or excessively large cracks.
Prevented. Suitable gas releasing agents include flammable oils;
There is soap and wax. Combustible oil as gas release agent in carbonaceous binder
Can be used. During curing of phenolic resin
To avoid oil evaporation, the boiling point of the oil is set at the hardening point of the resin.
It is desirable that it be higher than the temperature. For that reason,
Boiling above about 150°C, preferably above about 200°C
Oils with a boiling point higher than about 250°C are useful.
Particularly preferred are oils with spots. paraffin oil, aromatic
Petroleum-based oils such as aromatic oils and asphalt oils are preferred.
Although preferred, other oils such as animal or vegetable oils may also be used.
Among petroleum oils, paraffin oil is preferred. use
Examples of animal and vegetable oils obtained include palm kernel oil, olive
oil, peanut oil, tallow oil, cottonseed oil, corn
There are soybean oil, soybean oil, etc. For the coating composition,
up to 3.5% by weight, preferably from about 0.4 to about 2.0% by weight
Appropriate amount of oil. Soap may also be used as a gas release agent. use
Soaps are metal salts of fatty acids or quaternary ammonium
Any salt will do, but neutral or acidic quaternary ammonium
Binding agents using barium soap are more common.
Antioxidant than carbon cement made with metal soap
is high. Therefore, it is preferable to use non-metallic soaps.
stomach. To make this non-metallic soap, fatty acids are
React with ethanolamine. Fatty acid used
Similar to fatty acids used in the production of metallic soaps,
It has about 10 to about 24 carbon atoms and is either saturated or unsaturated.
It can be anything else. Among the available saturated fatty acids
contains capric acid, lauric acid, myristic acid, and patric acid.
Lumitic acid, stearic acid, arachidic acid, behen
acid, tetracosanoic acid, etc. typical insatiation
Japanese fatty acids include palmitoleic acid and oleic acid.
acids, linoleic acid, arachidonic acid, cetoleic acid,
These include erucic acid and ceracoleic acid. hopscotch
The amount of water is about 0 to about 15% based on the coating composition.
% by weight, preferably about 0.5 to about 5.0% by weight.
be. Various waxes are also used as gas release agents.
Ru. Suitable waxes include various petroleum waxes.
Among them are various ordinary paraffin waxes.
[e.g. purified slack wax, sweating]
(sweat) wax, scale (scale) wax
blocks, blocks, and microphones
Locrystalline wax]. A preferred binder system is a union carver.
Product name sold by ID: UCAR Made by C-34
It is a quality item. This composition contains oil, soap, finely ground
Carbon particles, furfuryl alcohol, novolak type
phenolic resin, and a curing agent for the resin
It is thought to contain a mixture of oil, fine powder
Crushed carbon particles, phenolic resin and phenolic tree
To obtain a mixture of fat hardeners, carbonaceous particles,
Nol resin and phenol resin curing agent using conventional methods.
mixed by any means (e.g. in a tumbler)
Sprinkle oil into the resulting mixture and mix again.
to distribute the oil throughout the mixture and make it substantially even.
Get a consistent blend. Soap and furfuryl alco
To obtain a soap mixture, heat the soap to approximately 100°C.
Heat it to liquefy it, then pour this molten soap
Dissolve in alcohol. Even after cooling, the soap
is dissolved as a stable solution in furfuryl alcohol.
This solution is mixed with another mixture (oil,
Crushed carbonaceous particles, phenolic resin, phenolic tree
It can be stored until mixed with fat hardening agent).
A mixture of two (one liquid and the other essentially solid)
body) at room temperature by manual or mechanical methods.
mixed with UCAR In C-34 cement, novola
Various types of phenolic resins can be used. this
In order to produce resin, phenol (phenol
itself, m-cresol, p-cresol, o
-cresol, 3,5-xylenol, 3,4-
xylenol, 2,5-xylenol, p-ethyl
Luphenol, p-tert-butylphenol, p
-amylphenol, p-tert-octylphenol
p-phenylphenol, 2,3,5-tol, p-phenylphenol,
(limethylphenol, resorcinol, etc.)
Aldehydes (formaldehyde, furfural,
acetaldehyde, etc.). actually
is a phenol that is not substituted due to cost.
- Formaldehyde resins can be used.
To cure novolak resin to a thermoset state,
Curing methods traditionally used to cure Borac resin
This can be done using any of the following agents. these
The curing agent is a conventional one (paraformaldehyde).
do, furfural, hexamethylenetetramine,
etc.) and can be used with an appropriate catalyst if necessary.
Ru. When heated, these curing agents release aldehydes.
The aldehyde reacts with the resin and crosslinks the resin.
cause to happen. UCAR Used in C-34 cement
The appropriate amount of novolac resin to be applied to the coating composition is approximately
0.5 to about 15% by weight, most preferably about 2.5 to about 15% by weight
It is approximately 8% by weight. Curing agent for resin hardens resin
only in sufficient quantity to cure to a state, i.e.
It reacts with the resin to cause crosslinking in the resin.
Provides at least the necessary formaldehyde and
is the amount that provides the alkaline catalyst necessary for the reaction of
It is used. UCAR As a component of C-34 carbonaceous cement,
Various forms of pulverized carbon or graphite can be used.
can. Suitable carbonaceous materials include graphite powder, petroleum
Coke powder, pitch coke powder, calcined oil smoke powder, sa
-thermatomic black
(created by passing natural gas over heat refractory material), etc.
Ru. The amount of carbonaceous powder is approximately
1 to about 60% by weight, preferably about 10 to about 40% by weight.
Appropriate. Most preferably, the carbonaceous powder is graphite
It is a mixture of
In that case, graphite powder is about 2 to about 50% by weight, Thermato
Mitsuku Bratsuku is about 2 to about 50% by weight, Thermato
Mitsuku and Bratsuku account for about 0.5 to about 25% by weight. UCAR Furfurylal in C-34 cement
It is appropriate to use alcohol, and the alcohol is
from about 2% to about 40% by weight of the coating composition, most preferably
or about 4% to about 20% by weight. Other suitable carbon cements are commercially available.
For example, there are the following. UCAR C-
38 (Union Carbide) is UCA to C-34
It has a similar composition and contains antioxidants.
Stebbins AR-25-HT is a furan resin composition.
, furfuryl alcohol, difurfuryl ether
Partially polymerized furan resins in the form of
Latent catalyst that can be phthalic acid or its derivatives
It's getting more familiar. Stebbins AR-20-C is
Difurfura ether together with rufuryl aldehyde
Partially polymerized furan resin and anhydrous lid shaped like
Contains latent catalysts that can be acid or its derivatives.
I'm here. Atlas CARBO−KOREZ is phenol
It is a resin composition, and the phenolic property in the solid is
When placed in a solvent (mixture) that has been hardened by
Contains high-quality phenol novolak or resol resin.
nothing. This solvent is probably something like butyl alcohol.
It is an aliphatic alcohol. Other suitable carbon cement
The following can be mentioned as examples. Atlas
CARBO-ALKOR is furfuryl alcohol monomer.
some polymers such as difurfuryl ether,
and phthalic anhydride or its derivatives.
Contains latent catalyst. DYLON GC is a solvent
furfuryl alcohol, phenol phor as
Monomers that harden with maldehyde, as well as
Contains sameethylenetetramine curing agent. Aremco
GRAPHI-BOND 551-R is furfuryl al
Contains coal and latent catalysts. The coating composition is applied in a single layer or on the cathode of an aluminum bath.
can be used in multiple layers. Multilayer coating system
If , TiB₂The first bonding layer that does not contain
Stronger as it penetrates better and deeper into the void structure of the poles
A strong bond is obtained and the applied material hardens more easily and more quickly.
become Additionally, using multiple layers reduces the TiB₂Contains
Shrinkage, crack size and number in the top layer of
Decrease. In yet another preferred embodiment
The coating composition typically contains up to about 10% carbon by weight.
It can contain fibers. Carbon fiber is cracked
Prevention of cracking, strengthening of applied materials, especially at points of contact with the bath
It has the effect of reducing the tendency of the applied material to peel off.
have Carbon cement used in cathode substrate as bonding layer
Up to 40% more carbonaceous fillers and additives
on the cathode substrate and the bonding layer.
Improve the bonding strength with the bonding layer and the properties of the bonding layer, and apply
Cathode caused by stress generated during hardening and carbonization of materials
Helps prevent cracks in the base. The coated cathode disclosed herein is a conventional aluminum cathode.
Mini tank or both anode and cathode are tilted from horizontal
It can be used in tanks without any problems. These Al
The minium tank is described in the prior art literature (Lewis et al.
No. 3400061, Holiday U.S. Patent No. 3661736
No. 4,093,524) and Payne U.S. Pat.
It is being proposed. Their shape is that aluminum
It has the advantage of being easily extracted, and therefore,
The surface of the cathode wetted with aluminum is coated with aluminum.
Only a thin film of the film remains, resulting in a narrower anode-cathode distance.
becomes possible. However, commercially available applications
Create a tilted cathode or RHM tile surface for the cathode
Past attempts to do so have been unsuccessful. Additionally, the concepts disclosed herein also apply to non-consumable
Also suitable for aluminum reduction tanks that use electrodes.
It is possible to use it. This anode is porous like platinum black.
It can be made of a highly conductive material, and the electrolyte can pass through it.
Oxygen ionizer made of ceramic that is resistant to electrolytes.
It is separated from the molten electrolyte by an on-conducting layer.
Ru. Oxygen ions are transported through the oxide layer to the anode
is released, producing oxygen gas. That anode
marcinek U.S. Patent No.
Disclosed in No. 3562135. Schmidt
Hatting and Huwyler
No. 3578580 describes an anode based on a similar principle,
However, molten silver or an auxiliary electrolyte (e.g.
Anodes containing PbO) and solid conductors or platinum are disclosed.
It is. SnO₂Anode based on Klein
(Klein) US Pat. No. 3,718,550 and Adler
(Adler) US Pat. Nos. 3,930,967 and 3,960,678
and No. 3974046. Furthermore, de
De Nora et al., U.S. Patent No. 4,098,669
Leave, Y₂O₃and other compounds.
It has a matrix and an electrocatalytic on the surface.
Discloses the use of sintered electrodes with materials. Ho
More complex for aluminum electrolysis
A coarse oxide anode with electrically conductive spinel ash
Tanite, delahosite, pyrochlore, scheelite and
and mixtures thereof.
The anode is a patent to Yamada et al., a U.S. patent.
No. 4039401, British Patent No. 1508876, Japanese Patent Publication No.
Patent No. 140411 (1977) and Japanese Published Patent No.
No. 153816 (1977). The advantages of inert anodes are short ACD and tank design.
It is compact and has low heat loss.
Ru. Until now, inert yang and yin dissipated initial electrical energy.
This shows that the cost is disadvantageous compared to consumable carbon anodes.
However, the surface irregularity is small and the lifespan is quite long.
Therefore, frequent replacement of the anode and accompanying
The effect on tank operation is avoided. Such an anode may be made of the aluminum disclosed herein.
For use with a cathode that has a wettable surface
This has the advantage of reducing ACD size and extending its life.
is obtained. Disclosed herein, RHM-Carbon
Slanted or drained with application surface
Using such an anode in combination with a (drained) cathode
In this case, further advantages may be expected. Furthermore, the electrolytic cell described in the present invention is a conventional aluminum electrolytic cell.
Is it better than what is currently used in the aluminum tank?
It is thought that a thinner carbon cathode block could be used.
Ru. Because it has the potential to extend the life of the applied material,
Therefore, a thick cathode block is no longer necessary and can be used
Lower conductor temperature reduces costs and saves power
You can get a lot of information about it. Furthermore, the electrolytic cell of the present invention
RHM surface layer with wettability to aluminum
It is considered that a carbonaceous cathode substrate protected by
available. Practical scale using a coated cathode according to the invention
(105Kamp) VSS aluminum reduction tank was put into operation.
As a result, productivity improvements resulting from the present invention will continue.
Be looked at. Although the following is not an example of the claimed invention,
Process preferences for reference examples of improved coating compositions
Although it represents a high standard, many similar methods
A certain coating can be obtained. Example
collector bar
Assemble the cathode block on the cell ramming pro.
Before performing the cell ramming process,
Industrial sites where cathode blocks are applied
If the bottom and sides of the cathode are compacted by coating in the tank,
It is possible to coat all or part of the surface.
The entire cathode coating is then placed on the coated cathode, for example.
One operation using a heated hooded heater
It can be hardened and carbonized. This results in time
and application cost savings, ram joints
A complete monolithic cathode without (ram joint) is provided;
Furthermore, the amount of gas generated during bake-in is reduced.
The baking process has been improved to reduce slots.
and improved baked ram on the side walls.
generate. The coating composition ensures that each cathode block remains in its original position.
Before installation, the block is coated and hardened with carbonized
can be done. Alternatively, assemble the cathode
Press down, apply the coating composition, and then cure.
Both are possible. In this case, the carbonization process is carried out in the tank.
Now. Curing may be carried out in several stages.
As a result, the coated substrate gradually reaches the desired curing temperature.
is pulled up, creating a relatively hard surface at that temperature.
Carbonization is then carried out at a maximum temperature of 1100°C. this
In the early stage of curing, the mixture liquid volatiles and
Volatile components such as reaction products are removed and
On the other hand, at higher temperatures (e.g. 250°C to 1100°C),
Decomposition of carbonaceous materials such as cross-linked phenolic resins
However, a non-graphitizable carbonaceous matrix containing RHM remains.
This carbonization heats the coated cathode substrate to the desired temperature.
Immediately after initial curing, or the cathode substrate
This can be done after the is installed in the electrolytic cell. another
As a method, after coating and initial curing, carbon cathode blot
Place the cathode in the correct position in the tank, then attach the coated cathode.
Bake-in is performed by starting and operating the tank.
in)”. Alternative order: application-curing-
Carbonization - assembly - installation - ramming also
Adoptable. The coating area is from the entire inner surface of the cathode recess to the area under the anode.
Covering 10% or less (excluding 10%) of the cathode surface
Can be done. The coating area is 50% of the cathode surface directly under the anode.
~100%, preferably 70-100%. but,
It may be desirable to leave some uncoated parts.
do not have. Thereby, for example, tank heating and starting
At times, outgassing from the cathode ram can occur. RHM coating must be continuous on all cathode surfaces
There isn't. TiB₂For tiles, adjacent tiles
A small gap (1-5 mm) is bridged with molten metal.
Similarly, TiB at an appropriate concentration on the carbon surface₂particles exist
If so, the adjacent TiB₂Crosslinking occurs between particles.
An apparently continuous aluminum wet film is formed.
do. In the case of the composition of the present invention, in the surface of the cathode substrate,
TiB to₂When present at 20% by weight, pseudo-aluminum
A wet surface is created. TiB in surface layer₂The concentration is
35-60% by weight is preferred. In that case, foreign matter may be mixed
This will extend the life of the coating. RHM
Improve the properties of the particles or change the composition of the coating composition.
and/or change the distribution of RHM in the coating.
By doing so, the amount of RHM used can be reduced.
Cracks that occur in the coating are smaller than 5 mm in width.
Must be small, preferably smaller than 1mm
It is. Two different types of TiB₂was used in the test tank. High purity
(+99.5%) of TiB₂with a lower purity (98
%) TiB₂Even if you replace it with
No difference was observed. Carbon is used to produce high-purity powders.
Lower cost, lower purity powder using reduction method
The arc melting method was used to produce the powder. No minimum or maximum coating thickness has yet been specified.
However, the greater the thickness, the longer the life of the coating film. deer
However, in that case, cracks tend to become worse,
The cost will be high. The coating thickness is determined by the coating thickness during curing and carbonization.
Minimizes the tendency for blistering and cracking in the membrane
Therefore, about 1 to about 1.6 cm is preferred. coating thickness
The maximum value should correspond to the expected bath life.
Ru. In other words, the tank life is expected to be only 7 years.
In some cases, the coating thickness does not need to last for 10 years.
do not have. Alternatively, the coating composition may be applied in a single layer or in multiple layers.
It is possible that In the latter case, curing occurs after each application.
It is done every time. According to this idea, the application composition
Applying thin layers of paint several times and curing each time.
Due to the
It is possible to obtain Maximize bond strength
To ensure that the surface of each cured layer is coated before applying the next layer,
For example, scuffing and wire
It may be desirable to handle the
stomach. This technology allows the RHM concentration of each layer coating composition to be increased.
By varying the degree of RHM concentration during curing,
It is also possible to change it hierarchically. Coat each cathode block, assemble the cathode, and open the tank.
General procedure used when cutting in
is as follows. 1. Wire the upper surface of the cathode block,
Vacuum clean. 2 Attach a mold to the top of each cathode block. 3. Mix dry application ingredients. 4. Preheat coating ingredients and block. 5. Mix the coating composition. 6 Apply a thin layer of coating composition to the block surface.
Let it soak in. 7 Finish applying the coating composition and apply using a stick.
Match the height of the object with the top of the mold. 8 After 15 to 30 minutes, use a metal trowel to apply the
Make the surface almost smooth. 9 Insert the thermocouple during curing and harden the coating block.
Put it in the chemical pot. 10 Perform curing. 11 Remove the mold from the block. 12 Place the hardening block into the metal box and
Cover with oak and heat to partially carbonize. 13 After cooling the block, remove it from the coke bed.
Take out the lock. 14 Cast a block on the collector bar
Ru. 15 Remove each collector bar assembly from the cathode.
Firm up the inside of de Ciel and firm up the side walls. 16 Applying excess ram
Wire away from the surface layer. 17 Follow conventional procedures to install and bake the cathode.
and cut in. The uniformity, workability, and bonding strength of coating compositions depend on temperature.
greatly influenced by. The mixture of coating compositions and
The premixing temperature of the solid part and solid part is 40-45℃ and
30-35°C is preferred. 20-45 as premix temperature
°C was used for both the mix liquid and the solid part;
No major problems arose. shade to be applied
The temperature of the polar block or its surface is 20-65℃, preferably
It is necessary that the temperature is 40 to 50°C. preliminary mix
If the mixing temperature is low, uniform mixing will not be achieved and the coating assembly will be
Addition of extra solvent to make the product workable
It becomes necessary. In either case, small amounts of
There was swelling. If the premix temperature is high, the coating
Early curing occurs in some parts of the composition, reducing workability.
The bonding strength to the carbon substrate decreased. Lower cathode block temperatures result in more uniform coating compositions.
to obtain the wetting of the carbon substrate necessary for good bonding.
I couldn't do it. If the block temperature is high
, some premature curing occurs and the applied material shrinks excessively.
Ta. Excessive shrinkage may cause cracking tendency as well as carbon substrate
Increased peeling tendency. As mentioned above, the preparation of the coating composition and cathode block is
For heat treatment, there is a certain temperature range that can be applied.
Exists. It should also be noted that the coating thickness
It can range from approximately 0.6 to 1.6 cm or more. preferred
The table shows the range.

Table: The tendency for blistering in coatings depended on the technique and degree of finishing used to finish the upper surface of the coating. When the surface of the coating was dry or wet treated to give a smooth finish, the tendency for blisters to form was greater than when the surface was roughened with a trowel. The smooth surface provided rapid formation and sealed the surface, preventing the release of gases (which would lead to blistering) during curing. Conversely, the partially smooth, imperfect surface facilitated outgassing during the curing cycle. The surfaces of eight blocks coated with the composition shown in Example 6 were treated by wet and dry methods to make them smooth.
After curing, blistering in the coating of these blocks was observed. When the same composition was applied to another 52 blocks and the surface of the coating was only slightly smoothed, a blistering coating was obtained. The surface conditions of various finishes applied to coatings made from the coating composition of Example 8 were characterized. The technique used in this case was to take a 2 cm x 2 cm x 2 cm coating block and place it in epoxy resin filled with white powder to create a white background for the black paint film. The specimen was fractionated and polished to reveal the detailed condition of the coating surface. This surface condition is magnified at 12x.
I took a photograph and traced the appearance of the paint film surface on a piece of paper. A representative 5 mm fraction of this surface condition was analyzed and the maximum peak-to-valley height and average value were calculated. These measurements are shown in the table.

[Table] Although the coated cathode with a fairly smooth finish showed blistering in both the dry and wet methods, the coating film of the coated cathode with a semi-smooth finish was usable for practical use. Therefore,
Surface conditions with an average peak-to-valley height of less than 0.65 mm are considered not to be used. UCAR 6 for high porosity graphite particles (UCAR BB-6) or other similar porosity particles
The release of solvents and other gases during the hardening and carbonization cycles was easier than with common coke materials such as -03 coke. Addition of porous particles to coating compositions reduced the tendency for blistering and the amount of shrinkage of the coating during curing. If the shrinkage is too large, the coating film-substrate bond strength will be weakened and many cracks will be formed. Example 1 Charcoal production rate Various carbon systems (solid components) were prepared using mix liquids with accurately determined weights in a size of 5.1 cm x 1.27 cm x 0.63 cm.
(depth) of Teflon and mixed in a mold. If the carbon system contained another curing agent, the weight of that curing agent was included in the weight of the mix solution. Each carbon system was subjected to a normal curing cycle, weighed, and demolded. The cured pieces were then brought to constant weight in an alumina crucible at 250°C in air to compensate for any weight loss that might have occurred during demolding (e.g., breakage, pulverization, adhesion to the mold). . That weight was the true weight that the sample would have obtained at 250°C without physical manipulation. The test pieces brought to constant weight were then sintered at 1000° C. for 24 hours under an argon atmosphere in an alumina crucible. After cooling the furnace, the samples were weighed and again corrected to a weight corresponding to the original weight of the composition (rather than the weight used in the sintering step). The corrected charcoal weight represents the total charcoal weight obtained from the original sample. Accurately weighed original solids were subjected to extraction with boiling MEK in a Soxhlet extractor for 4 hours, or longer if the extraction liquid continued to accumulate after 4 hours. The weight of the extracted material was determined by evaporating the solvent to dryness (at least 24 hours) in a tall glass beaker kept in a vacuum kettle at ambient temperature. The weight increase relative to the empty beaker was taken as the weight of the extracted substance. This weight was compared to the weight of undissolved material remaining in the Soxhlet extractor thinble (also evaporated to dryness under vacuum to constant weight). The weight of MEK insolubles in the original carbon system is calculated from the known weights of solids originally present and the percentage of those solids that contain MEK insolubles. These solids appeared to suffer no weight loss up to 250°C. Therefore, the weight of "resin" (in this case defined as everything in the 250°C cured carbon system other than MEK insolubles) in the 250°C sample is equal to the weight of the true sample at 250°C. It is given as the weight minus the weight of MEK insolubles initially present. To measure the weight of coal due to MEK insoluble matter, the extraction residue taken from the Soxhlet thimble was sintered at 1000°C in an alumina crucible under an argon atmosphere. The MEK initially present in the starting sample was
Insoluble matter was subtracted. The charcoal weight coming from the resin is therefore the total charcoal weight.
The charcoal weight of the MEK insoluble portion was subtracted.
"Charcoal production rate" was the weight of char coming from the resin as a % of the total resin weight in the 250°C slug. The results of these measurements are shown below.

[Table] Example 2 Expansion rate A coating composition sample was prepared, and the size was 5.1 cm x 1.25 cm x 0.63 cm.
cm (depth) spread into a Teflon mold. This was subjected to a normal curing cycle, cooled and demolded. Four specimen pieces, each 2.5 cm x 0.6 cm x 0.6 cm, were cut and dried in an alumina crucible at 250°C (usually 16-24 hours) to constant weight. The specimens were measured with a micrometer and then heated from room temperature to 1000° C. in a dilatometer with a constant flow of argon. Expansion/contraction was constantly recorded on an XY recorder as a function of temperature. Two shrinkage values were calculated. One is the initial sample length and
One is based on the length at 1000°C and the other is based on the initial sample length and the final length after the sample returns to room temperature. The final length of the sample was also measured using a micrometer after cooling as a double check of the recorder value. The test samples were as shown in the table. Despite very careful sample preparation and uniform temperature cycling, the total expansion of the various coating compositions appears to be relatively unreproducible. However, after carbonization, the expansion of the coating composition at 800 DEG -1000 DEG C. is found to be well reproducible and very similar to the expansion of the block. Furthermore, it is found that in this temperature range, UCAR C-34 cement exhibits expansion that is unusable on its own. The coating is believed to be sufficiently strained to tolerate any CTE mismatch between the coating and the cathode substrate up to the point of complete carbonization (approximately 800° C.). Beyond this point, the coating becomes hard and brittle, and therefore the presence of a CTE difference will cause internal stresses and large cracks to form.

[Table] Example 3 The following ingredients were mixed to form a coating composition (CM-
24A) was created. % is by weight. TiB ₂ , -325 mesh 36% UCAR C-34 carbon cement solid 34.2〃 UCAR C-34 mix liquid 19.7〃 Calcined petroleum coke particles, grade 6-03 (Union Carbide) 10.1〃 The resulting coating composition was 7.5 cm x A 15 cm cathode block substrate was coated. A sufficient amount was applied to give a thickness of approximately 0.16 cm, and a larger amount was applied to the surface of the block to obtain a layer thickness of 1.59 cm and smoothed. The coating was cured by heating to 100°C at a rate of 25°C per hour, held for 5 hours, heated to 140°C at a rate of 25°C per hour, held for 24 hours, and returned to room temperature by air cooling. After curing, some cracks were observed, but the paint film was
Substrate bonding was unaffected. Example 4 A coating composition (CM-
37). TiB ₂ , -325 mesh 36% UCAR C-34 cement solid 29.4〃 UCAR C-34 mixture liquid 32.4〃 Great Lakes Carbon FORTAFIL (0.63 cm long unsized fiber) 2.2% The resulting coating composition was 7.5 cm x A 15 cm cathode block substrate was coated and cured in the same manner as described in Example 3. After curing, this coating did not exhibit the cracking seen in the carbon particle coating of Example 3. The carbon fibers appear to act as anti-cracking agents in the cathode coating, thereby extending cathode life. Example 5 A 7.5 cm x 15 cm cathode block was used as a substrate for a coating composition (CM-38A) having the following composition. TiB ₂ 37.5% UCAR C-34 cement solid 30.6〃 UCAR C-34 mixture liquid 29.6〃 FORTAFIL (unsized carbon fiber) 2.3〃 This composition was applied in the same manner as in Example 3,
The final thickness was 0.95 cm. The coating was cured according to the following cycle.
The coating block was heated to 100°C at a rate of 25°C per hour.
It was kept at this temperature for 3 hours. 140 at a rate of 25°C per hour
℃ and kept the block at that temperature for 16 hours. The coated block was then taken out and cooled in the air to room temperature. Upon inspection, no surface blisters, cracks, or bonding defects were found. The cured block was then carbonized by heating to 1000° C. for 24 hours in an argon atmosphere (to avoid oxidation). Then 200 min in an argon atmosphere.
It was cooled to a temperature lower than °C, taken out, and returned to room temperature. Upon inspection after cooling, no defects were found. The shape as well as the bond to the substrate was unaffected by carbonization. Example 6 The coating process for a small test block (7.5 cm x 15 cm) was applied to a practical scale cathode block (50.2 cm x 52.1 cm).
cm), the amount of mix liquid was reduced from approximately 20-32% by weight to 15-19% by weight. When the utility scale cathode blocks were coated using compositions with higher solvent concentrations, blisters formed during the curing cycle. As the "surface area to surrounding ratio" of the coating block increased, the tendency of the coating to blister increased. That is, it became difficult for the solvent to volatilize during the curing cycle. Moreover, as the coating thickness increased, the blistering increased. That is, the coating film with a thickness of 0.32 cm showed almost no tendency to blister, whereas the coating film with a thickness of 1.27 cm had a strong tendency to blister.
A blistering-free coating was obtained on the cathode block using the following composition (CM-66). TiB ₂ , -325 mesh 36% by weight UCAR C-34 cement solid 36.35 〃 UCA C-34 mixture liquid 19.3 〃 Great Lakes Carbon FORTAFIL 3 (0.63cm
Length, unsized carbon fibers) 0.3 UCAR BB-6 graphite particles 8.0 Using a cathode coated with the above composition to a thickness of 0.63 cm,
An industrial VSS aluminum reduction tank was experimentally operated for 310 days. Regarding the last nine months of driving,
The energy efficiency of the tank is lower than the average for this plant per 0.45 kg (1 lb) of aluminum produced.
It was 0.14Kwh low. After 310 days of operation, the test chamber (A-43) was cut open and the molten metal and bath removed, leaving less than 5 cm of metal at the bottom of the cathode well. Examination of a 4.5 cm diameter core sample taken from the test cathode after cooling showed that the coating loss was consistent with the expected coating life determined from metallurgical analysis. (i.e. approximately 1/3 of the original coating thickness was lost.) In the cathode separation zone, there was apparently complete loss of coating. A cathode core sample taken from the cut test tank A-46 (Table) confirmed that the coating loss was consistent with the expected coating life determined from metallurgical analysis. There was no damage to the coating or formation of mud on the cathode surface of this tank. Example 7 The fiber content in the composition was reduced to reduce the tendency to form blisters, since lowering the fiber content reduces the amount of solvent required to impart workability to the coating composition. However, there was a tendency for fine vertical cracks to form in the coating. These cracks allowed solvent volatilization during curing, thus reducing blistering. Using the following composition (CM-78B), a coating film with no blisters and fine cracks was obtained on a cathode block. TiB ₂ , -325 mesh 46.0% by weight UCAR C-34 cement solids 28.5% by weight UCA C-34 mix liquid 15.5 〃 UCAR BB-6 graphite particles 10.0 〃 In the early stages of testing this composition, the coating surface was extremely smooth. I faced many problems because I tried to make it. After applying the coating composition to the cathode substrate, it was wetted with excess mix solution and completely smoothed. This smooth coating film developed blisters due to curing. By using excess mix solution, a "skin" was formed on the surface of the coating film during curing, which prevented the volatilization of generated gases. As a result, blistering occurred, resulting in a defective coating film. After that, a light surface finish was applied to the surface of the coating without the use of excess mixing solution, and an acceptable cured surface was obtained without any blistering. It has also been found that ambient temperature is related to the mixing and spreading properties of coating compositions, with lower ambient temperatures resulting in compositions that are harder and more difficult to coat. While the vertical cracks are small, the cracks do not adversely affect the functionality of the coating. Assuming a constant dissolution rate of TiB ₂ , the TiB ₂ concentration was increased in this composition to increase film life. This composition 0.95
An industrial VSS aluminum reduction tank was experimentally operated for longer than 225 days using a cm-thick coated cathode. The energy efficiency of the tank for the last 6 months is
This was 0.19 Kwh less per 0.45 Kg (1 pound) of aluminum produced than the plant's average value. Example 8 The composition of Example 7 was modified to reduce the number of vertical cracks in the coating. However, the solvent content was not changed to prevent blistering. Preferred compositions (CM-82 and CM-82A) are as follows, and the resin binder used therein had a charcoal production rate of 94% as measured by charcoal production rate analysis. CM−82 TiB ₂ powder, carbon random −325 mesh
46.0% by weight UCA C-34 cement solid 28.0 〃 UCAR C-34 mix liquid 15.8 〃 Great Lakes Carbon FORTAFIL 3 (UCAR
C-34 Cement sized carbon fiber, 0.32cm
long) 0.2 〃 UCAR BB-6 graphite particles 10.0 〃 CM-82S TiB ₂ powder, Metallurg, -325 mesh 46.0% by weight UCAR C-34 cement solid 28.0 〃 UCAR C-34 mix liquid 15.8 〃 Great Lakes Carbon FORTAFIL 3 (UCAR
C-34 Sized carbon fiber for cement, 0.32cm
0.2 UCAR BB-6 Graphite Particles 10.0 The above composition was successfully applied to 0.95 cm of cathode blocks for two industrial scale VSS aluminum reduction test cells and the cells were operated for 125 days. The number of longitudinal cracks in the coating virtually dropped to zero.
The energy efficiency of the tank during the last two months was 0.08 and 0.05 Kwh lower than the average for the plant, respectively, per 0.45 Kg (1 lb) of aluminum produced. In preparing the coated cathode block of this example, the block was preheated to 40-50°C prior to coating at lower ambient temperatures to provide a good coating composition to avoid the need for extra mix solution. Improved workability. It has also been found that preheating the dry and liquid components of the coating composition prior to their mixing improves the mixing and coating properties of the coating composition. Furthermore, when the concentration of the mix solution was reduced, the formation of blisters was reduced. Additional tests were conducted using various compositions and preheating the cathode block. It has been found that preheating the blocks to 70-80 DEG C. makes application very smooth and easy, but causes premature curing and excessive shrinkage and peeling. It has also been found that a preheating temperature of 40-50°C provides the best combination of workability and reduced shrinkage of the coating composition. The coating compositions described above as well as additional compositions made and used for industrial VSS aluminum bath cathode blocks are summarized in the table below. In the same table, the energy efficiency is 0.45Kg (1 pound) of manufactured aluminum.
The expected coating life is based on the dissolution of TiB ₂ into the resulting aluminum. At an energy cost of 22 mils per Kwh, the savings are expected to be on the order of $10 per ton.

【table】

[Table] R○
Carbon FORTAFIL 3) Unsized
Sizing Sizing Sizing
In addition to the commercially available carbon cement UCAR C-34 used in the previous examples, various thermosetting carbon cements were used to prepare the coating compositions. In most cases good coatings were obtained. In most cases where the quality of the coating after curing and carbonization is poor, it is believed that good coatings will be obtained if the respective necessary modifications are made to the coating compositions. Example 9 The following ingredients were combined and mixed to make a coating composition (CM-89). TiB ₂ 36.5% UCAR C-37 Carbon Cement Solid 34.6〃 UCAR C-37 Mixture Liquid 19.2〃 UCAR BB-6 Graphite Particles 9.7〃 This composition has The composition is essentially the same as that of UCAR C-34 carbon cement. This material is relatively easy to work with, has fluidity, and is
0.95cm on SK cathode block (7.5cm x 15cm x 5cm)
When applied thickly, it spread easily and hardly stuck to work tools. To cure the coated block, the temperature was raised from room temperature to 100°C over a period of 1 hour. After keeping it at that temperature for 4 hours, it was heated to 135℃ for 1 hour.
Hold at that temperature for 4 hours, heat to 150℃ for 1 hour, keep at that temperature for 12 hours, heat to 165℃ for 1 hour.
℃ and held at that temperature for 3 hours, then air cooled. Although the cured coating showed peeling at the outer edge of the cathode substrate surface due to shrinkage, the internal porosity was small, there were very few horizontal cracks, and there were no surface defects. Then, in order to carbonize the coated cathode substrate, it was heated to 1000° C. for 24 hours in an argon atmosphere and allowed to cool to room temperature. Carbonization essentially destroyed the coating, leaving virtually no coating remaining on the substrate surface. This example illustrates the importance of selecting the carbonaceous additive used in the coating composition. In this particular example,
Incompatible additives were incorporated into the carbon cement resin, specifically graphite flake additives, which were suitable for causing expansion. Example 10 A coating composition (CM-
90) was created. TiB ₂ , -325 mesh 35% UCAR C-38 carbon cement solid 33.4〃 UCAR C-38 mix liquid 22.2〃 UCAR BB-6 graphite particles 9.4〃 UCAR C-38 cement can be converted into UCAR C by adding antioxidant. It appears to be essentially the same as −34 carbon cement. This coating composition is
It exhibited good workability and fluidity and could be easily spread on the Sumitomo SK block described in Example 9. Then,
This coated block was cured as in Example 9. The cured coating composition exhibited very large subsurface blisters, good bonding, good density, and no surface defects. The carbonized coating film after carbonization similar to that described in Example 9 showed peeling due to shrinkage of the coating film, but
No surface defects were observed. It is believed that this coating composition can be used satisfactorily in the present invention and forms a bonding layer of carbon cement between the coating and the cathode substrate. Example 11 A coating composition (CM-87) having the following composition was prepared. TiB ₂ 33.6% Stebbins AR-20-C carbon cement solid 37.5〃 Stebbins AR-20-QC mix liquid 28.9〃 Stebbins AR-20-QC mix liquid contains partially polymerized furan resins such as furfuryl alcohol low resin polymers It seems to be. Latent catalysts such as furfural as well as phthalic anhydride may also be present. The cement solids of this carbon cement appear to include carbon powder along with catalyst and aniline modifier. This coating composition was applied to the cathode substrate in the same manner as described above, cured at 30°C for 24 hours, heated to 110°C over 3 hours, and maintained at that temperature for 24 hours.
This composition had poor workability, was hard, and was easily punctured before being applied to the cathode substrate, but the horizontal cracks after curing were very small. The cured coating was hard, with no blisters or large cracks, good density, and very strong bond to the substrate. The coating film carbonized in the same manner as in Example 9 had only a few cracks due to shrinkage, little peeling due to shrinkage, and a good density, but the fractured portions were large. Example 12 A similar coating composition (CM-
88). Stebbins AR-25-HT Carbon Cement Solid 38.7% Stebbins AR-25-HT Mix Liquid 28.3〃 TiB ₂ 33〃 This cement contains a modified furan resin of furfuryl alcohol, a low resin polymer of furfuryl alcohol, and a latent It seems to contain a catalyst.
The coating composition was hard, easily scratched, and had poor workability. The coated substrate was cured in the same manner as in Example 11. The properties of the cured coating film were similar to those of the cured coating film of Example 11. The coating film after carbonization showed greater shrinkage than that of Example 11 and peeled off. However, no fractures or cracks were observed in the surface layer. Example 13 A carbon-filled polyester resin, trade name Atlas CARBO-VITROPLAST carbon cement, was mixed with 35% TiB ₂ to form a coating composition (CM-92). This product had good workability, good fluidity, no stickiness, and easily spread on the cathode substrate as described in Example 9. To cure the coated substrate, heat it to 100℃ for 1 hour, keep it at that temperature for 3 hours, and heat it to 165℃ for 1 hour.
Heat to
℃ and kept for 1/2 hour and air cooled. The cured coating had excellent bonding strength to the substrate, excellent density, and no surface defects. As described in Example 9,
The coated substrate was then subjected to carbonization. The carbonized coating was completely peeled off, and although the coating was intact, it had small voids over a wide area. The coating showed no surface defects, but was very light and powdered easily. The resin binder used to make the present coating composition showed a char production rate of only 8%, demonstrating the importance of this parameter. Example 14 Atlas CARBO−ALKOR as per manufacturer's instructions
(Furan resin-based carbon cement with carbon filler)
and add enough TiB ₂ (35% of the blend)
I mixed it up. This coating composition (CM-93) showed very good workability. After curing as described in Example 13, the coating showed good bonding throughout the substrate, extensive fractures on the coating surface, and a reasonable density. The coating film after carbonization showed slight peeling, more extensive fracture, and large cracks on the surface due to shrinkage. A coating obtained by replacing 3.5% of the mix in this coating composition with 3.5% soap (a gas releasing agent) was acceptable. Example 15 A phenolic resin-based cement containing carbon filler, which appears to contain a solvent (butyl alcohol).
Using Atlas CARBO-KOREZ carbon cement,
Coating composition (CM-94) was prepared in the same manner as in Example 13.
I made it. The coating composition had very poor workability, was extremely hard, and was difficult to spread onto carbon substrates.
The cured coating film obtained in the same manner as in Example 13 had good bonding strength, good density, and no surface defects.
However, the coating after carbonization showed peeling due to shrinkage. Replacing the mix solution (butyl alcohol) of Atlas CARBO-KOREZ resin with furfuryl alcohol improves the impregnation of the cathode substrate.
Therefore, it is thought that the bonding strength is improved. Example 16 DYLON grade GC premixed with TiB ₂ 35%
A coating composition was prepared using carbon cement.
DYLON carbon cement is believed to contain less than 10% powdered coal tar pitch, less than 20% phenolic resin, and less than 35% furfuryl alcohol. This coating composition showed very good workability, but Example 9
The cured coating obtained in the same manner as in showed extensive large cracking and peeling. Significant horizontal cracking and high porosity were also observed. This coating did not appear to be worth carbonizing due to its poor condition after curing. To recombine this composition, add 3.5% soap (gas releasing agent)
% added, both the coating films after curing and after carbonization were excellent. This demonstrates the importance of the selection of addenda to the coating composition and indicates that failure of the coating composition is due to lack of porosity necessary for volatiles to evaporate. Example 17 TiB ₂ 45°C, premixed Aremco GRAPHI−
A coating composition was made using 55% BOND grade 551-R carbon cement. This carbon cement is
It appears to contain 60% graphite and 40% furfuryl alcohol, and was specially made for use in reducing pressure. This coating composition was smooth and could be applied to the cathode substrate relatively easily. When the coated substrate was cured in the same manner as described in Example 9, the coating bond was good and the density was reasonable, with vertical cracks near the edges and fine horizontal cracks over a wide area. occured. After carbonization, peeling occurred near the edges due to shrinkage, but the density of the coating film was reasonable, and large cracks in the vertical direction and fine cracks in the horizontal direction were present to some extent. It is believed that the addition of gas releasing agents and carbonaceous additives solves these problems. Example 18 Aremco GRAPHI−BOND Grade 551−
R (32% graphite and 68% sodium aluminum silicate
%) was used to prepare a coating composition in the same manner as in Example 17. This thing was very fluid and flowed rather than spreading. The coated substrate was subjected to curing as in Example 9, but at 100°C.
After 4 hours, huge blisters appeared in the paint film. Although the coating was extremely porous, the bond was good. The coating film after carbonization appeared to be unchanged, but it became more brittle and slight peeling was observed near the edges. This example illustrates an example of a coating composition that is unsuitable for the present invention. Example 19 Great Lakes pre-mixed TiB ₂ 45% and possibly based on graphite particles and binder
Using Carbon grade P-514 carbon cement,
Another coating composition was made. This was easy to work with and could be easily smoothed onto the cathode substrate. Cured in the same manner as in Example 9, 100°C, 4
In time, extensive large-scale porosity and fracture occurred. The bonding was good and the density between the pores was good. The coating had a shine, and the inside of the pores and under the fractured parts had a glass-like appearance. The coating film appeared unchanged after carbonization. However, large vertical cracks developed along the edges and slight delamination occurred. A modification of the composition by substituting 3.5% soap (a gas releasing agent) for the 3.5% mixture gave acceptable coatings. Example 20 1,3-Cyclohexadiene is polymerized using a Ziegler-Natsuta catalyst, followed by halogenation and dehydrohalogenation to produce a non-melting polyphenylene polymer. This results in a molecular weight of approximately 4000
A paraphenylene polymer is produced. Due to its relatively low molecular weight and relative insolubility, this resin alone is unsuitable for use in the present invention. Cationic oxidative polymerization of 1,3,5-triphenylenebenzene produces meltable polyphenylene resins (eg, soluble in trichlorobenzene).
The reaction product contains non-melting polyphenylene by-products and is removed by fractional distillation. Polyphenylene obtained by distillation has a molecular weight of 1000-1500. A coating composition is prepared using the above two resins as follows. The two resins are separately ground into a -325 mesh and thoroughly mixed in a high speed blender for 15 minutes. In this case, the ratio of the two is 1.6% by weight (based on the coating composition) for non-melting polyphenylene and 3.3% by weight for melting polyphenylene. Add 16.3% by weight of graphite powder (UCAR GP38P) to this mixture.
8.2% by weight of REGAL 400 pellets (carbon black from Cabot Corporation) were added. Triethanolamine (TEA) oleate 1.6
% by weight and 11.4% by weight of chloroform. TEA oleate is heated to 100°C to first make it liquid, then it is poured into chloroform. Random carbon in dry ingredients including polyphenylene resin powder, graphite powder and carbon black - 325TiB ₂ 47.3% by weight, union carbide
UCAR BB-6 graphite particles 9.8% by weight and Great
Add 0.5% by weight of Lakes Carbon FORTAFIL (0.32cm sized fiber). These ingredients are dry blended and a mixer is added to form a uniform dispersion. This coating composition is spread over the cathode block in the usual manner to form a 0.95 cm thick layer. The block is then left in the air for one hour to allow some of the solvent to evaporate. To effect curing, the coating block is slowly heated to 70°C to evaporate most of the mix, then slowly heated to 80°C and held at that temperature for 2 hours. Slowly raise the temperature again to 200℃ and keep for 8 hours. The block is then cooled to room temperature. Next, to perform partial carbonization, it was heated at 135°C for 9 hours, slowly raised to 300°C over 24 hours, and kept at that temperature for 6 hours. A satisfactory coating film can be obtained. Example 21 A coating composition (CM-91) having the following composition was prepared. TiB ₂ , -325 mesh, carborundum 44.9% UCAR C-34 carbon fiber solid 28〃 UCA C-34 mix liquid 14.7〃 UCAR 88-6 graphite 12〃 Great Lakes Carbon FORTAFIL 3 (0.32cm
Sized fiber) 0.4〃 Due to the high fiber content, it was difficult to mix this material. Poor dispersion of TiB ₂ required remixing of the composition halfway through the application run. This material was applied to a practical size cathode block and preheated to 50°C overnight. Application of this was difficult without heating the block. The coating film was leveled to 1.27 cm, semi-smoothed, and Example 9
It cured exactly as I said. After cooling, no defects were found. When the coating was subsequently cured, the bond was satisfactory and the surface was acceptable. It is understood that the foregoing description of the present invention can be modified and changed as appropriate by those skilled in the art. Further, such modifications and changes are to be considered within the scope of the invention as set forth in the claims.